What's the best way to use a single mouse and keyboard with two Macs simultaneously?

[Sal Collaziano]

There is so much craziness going on with viruses and malware that I'm beginning to feel it's best to have one computer specifically for email, and another computer - for everything else. My intention is to wall-off email entirely from my main computer.

I have seen this discussion - but it appears that person isn't using both computers simultaneously.

I have a 2017 iMac that I'm outgrowing and will probably replace it with a new Mac Mini Pro. I was trying to figure out what to do with the iMac's 27" inch monitor as it seems there's really no great solution to use it with a Mac Mini. I know solutions exist, but they don't sound too great to me.

So I'm thinking I'll just leave ALL my email (a lot) duties for the iMac and setup the Mac Mini Pro to handle everything else.

I'm just not sure how to use both the keyboard and mouse simultaneously with each computer. I use an Apple Magic Keyboard and a wired USB mouse.

Any suggestions?

 

[Bigwaff]

There is so much craziness going on with viruses and malware that I'm beginning to feel it's best to have one computer specifically for email, and another computer - for everything else. My intention is to wall-off email entirely from my main computer.

If you want to “wall-off” email, just use the web front end to your email provider instead of native email client. Separate computer just for email is overkill for your concerns. But, if you still intend to do this, you will need a KVM switch. Using KVM you can share keyboard and mouse (and display, if you so wish) with two computers.

Plus, having email on a computer which is not receiving security updates any more kind of defeats the purpose.

 

[meson]

Since you’re using two Macs that are new enough, the solution is baked into macOS and called Universal Control. I use it to bounce back and forth between my MBP and mini at work all the time.

 

[kitKAC]

If you REALLY want to do this... you could get the Mac Mini Pro, create a macOS Virtual machine on it, make sure it's completely isolated from the host machine, and switch on Lockdown mode for the guest macOS.

 

[HobeSoundDarryl]

Along with the KVM suggestion, you can also use a wireless keyboard- such as one from Logitech- that has 3 bluetooth "modes" to switch which computer it is controlling at the click a single button. I like MX Keys For Mac. If you look at the main picture, above the fn-home-page up keys, you'll see keys numbered 1, 2 and 3 with computer icons next to them. Or if you scroll down to overhead view, you'll see them more clearly, doubling as F13-15. Those are the "mode" buttons. I have 1 set to work with main Mac and 2 set for a PC. 3 awaits some other use.

Now, this option involves clicking one button to share the same keyboard with 2 computers, but the KVM option will also involve some kind of "trigger" to let it know which computer "owns" the keyboard at any given point in time. I don't think there will be any fully automatic way as there must be some way to tell keyboard and target computer that key presses should register on the target.

Depending on which monitor you use, some- like mine- has a built-in KVM. So if I used a wired keyboard with it, as I change monitor inputs to use different computers, the keyboard (and mouse and speakers and hubs, etc) would switch to being "owned" by whichever computer (input) is active at the time. If you are using something like ASD with only 1 input, you'll have to use separate KVM hardware or a keyboard like the Logitech one.

 

[Sal Collaziano]

If you want to “wall-off” email, just use the web front end to your email provider instead of native email client. Separate computer just for email is overkill for your concerns. But, if you still intend to do this, you will need a KVM switch. Using KVM you can share keyboard and mouse (and display, if you so wish) with two computers.

Plus, having email on a computer which is not receiving security updates any more kind of defeats the purpose.

If I were to use the Gmail interface on my main computer, and I click a malicious link, the action will be taken on the main computer - which is what I'm trying to avoid. I'm pretty good at figuring out what's safe or not - but as the bad actors improve, I want to stay as far away from a zero day exploit - or whatever - as I can.

My late 2017 iMac won't be receiving security updates anymore at some point this year - and I hadn't thought of that. So this may not work the way I was hoping anyway...

Since you’re using two Macs that are new enough, the solution is baked into macOS and called Universal Control. I use it to bounce back and forth between my MBP and mini at work all the time.

Would this option be as seamless as using three monitors on a single Mac and going back and forth through each one? If not, what might the difference be?

If you REALLY want to do this... you could get the Mac Mini Pro, create a macOS Virtual machine on it, make sure it's completely isolated from the host machine, and switch on Lockdown mode for the guest macOS.

I'm really looking for something as seamless as possible. In other words, I'd love to be able to simply pass the mouse through from one monitor to the next without there being any major difference from what I experience now with three monitors using one iMac.

Along with the KVM suggestion, you can also use a wireless keyboard- such as one from Logitech- that has 3 bluetooth "modes" to switch which computer it is controlling at the click a single button. I like MX Keys For Mac. If you look at the main picture, above the fn-home-page up keys, you'll see keys numbered 1, 2 and 3 with computer icons next to them. Or if you scroll down to overhead view, you'll see them more clearly, doubling as F13-15. Those are the "mode" buttons. I have 1 set to work with main Mac and 2 set for a PC. 3 awaits some other use.

Now, this option involves clicking one button to share the same keyboard with 2 computers, but the KVM option will also involve some kind of "trigger" to let it know which computer "owns" the keyboard at any given point in time. I don't think there will be any fully automatic way as there must be some way to tell keyboard and target computer that key presses should register on the target.

Depending on which monitor you use, some- like mine- has a built-in KVM. So if I used a wired keyboard with it, as I change monitor inputs to use different computers, the keyboard (and mouse and speakers and hubs, etc) would switch to being "owned" by whichever computer (input) is active at the time. If you are using something like ASD with only 1 input, you'll have to use separate KVM hardware or a keyboard like the Logitech one.

Clicking one button isn't really that big of a deal - so this could work... It would be nice, however, if the system knew to activate the keyboard on whichever screen/computer the mouse was currently using...

 

[meson]

Would this option be as seamless as using three monitors on a single Mac and going back and forth through each one? If not, what might the difference be?

With Universal Control, once you are logged into both machines with the same Apple ID/Apple Account and allow it to be used, you just take your pointer from one display to the next, just the same as using one Mac with multiple displays. It's quite seamless. Each Mac operates independently, but you can control both with the same set of input devices. I worked this way for about a year with my Mac and an old 2013 iMac with the Universal Control feature made available using OCLP.

The one hitch is that because the machines are acting as separate machines you can't drag windows from one machine to the other, but you can drag and drop documents, copy and paste, etc. It's great for using machines as complimentary devices, but requires adjustments to how you work compared to one machine with multiple displays. For your intended use, I think this is exactly what you are looking for.

macOS will also allow you to go into the displays settings on your 2017 iMac and allow it to be used wirelessly as an external display with extended desktop for your new mini similar to using the mini with multiple monitors attached. It works great for editing documents and the like, but if I recall correctly, I experienced syncing issues with audio and video when trying to show video content on the Mac acting as a display. It works okay, but just isn't as effective as the old Target Display Mode that required a wired connection.

A KVM switch, monitor with KVM built in, or peripherals that allow switching between devices would be the way I would go if I had a Windows or Linux PC that I wanted to use alongside a Mac.

 

[Sal Collaziano]

With Universal Control, once you are logged into both machines with the same Apple ID/Apple Account and allow it to be used, you just take your pointer from one display to the next, just the same as using one Mac with multiple displays. It's quite seamless. Each Mac operates independently, but you can control both with the same set of input devices. I worked this way for about a year with my Mac and an old 2013 iMac with the Universal Control feature made available using OCLP.

The one hitch is that because the machines are acting as separate machines you can't drag windows from one machine to the other, but you can drag and drop documents, copy and paste, etc. It's great for using machines as complimentary devices, but requires adjustments to how you work compared to one machine with multiple displays. For your intended use, I think this is exactly what you are looking for.

macOS will also allow you to go into the displays settings on your 2017 iMac and allow it to be used wirelessly as an external display with extended desktop for your new mini similar to using the mini with multiple monitors attached. It works great for editing documents and the like, but if I recall correctly, I experienced syncing issues with audio and video when trying to show video content on the Mac acting as a display. It works okay, but just isn't as effective as the old Target Display Mode that required a wired connection.

A KVM switch, monitor with KVM built in, or peripherals that allow switching between devices would be the way I would go if I had a Windows or Linux PC that I wanted to use alongside a Mac.

Universal Control sounds perfect. I won't need to drag windows from one screen/computer to another as I'll only be using the iMac for email. However, considering the ability to drag and drop documents exists - does that type of connectivity leave me open for potential issues that may reside on the iMac computer (viruses, malware) to infiltrate my newer computer? With the drag and drop functionality - it seems like one of those "where there's a will, there's a way" scenarios...

My other issue, now, is that the iMac is from 2017 and can't be upgraded past Ventura - and it'll probably be insecure for me to use it for anything. On the other hand, I do hear there are ways to upgrade to Sequoia through some type of program - but I haven't researched this because I've never felt the need until now...

Worst case scenario, maybe I'll buy one cheap Mac Mini for email and one for everything else. But it would really be nice if I could continue to use my flawless iMac and 27" screen - which I really like...

 

[CharlesShaw]

Worst case scenario, maybe I'll buy one cheap Mac Mini for email and one for everything else.

Universal Control also works great with the iPad, so maybe that is an option. I prefer to use a keyboard for Messages but only log into it on my iPad, so it's very handy to just drag the Mac cursor to the iPad for Messages.

 

[Sal Collaziano]

Universal Control also works great with the iPad, so maybe that is an option. I prefer to use a keyboard for Messages but only log into it on my iPad, so it's very handy to just drag the Mac cursor to the iPad for Messages.

I will consider this but I'll try OpenCore Legacy Patcher with my iMac first...

 

[Bigwaff]

If I were to use the Gmail interface on my main computer, and I click a malicious link, the action will be taken on the main computer - which is what I'm trying to avoid. I'm pretty good at figuring out what's safe or not - but as the bad actors improve, I want to stay as far away from a zero day exploit - or whatever - as I can.

Perhaps you should be approaching the problem differently. A firewall such as Little Snitch will stop any connections unless you explicitly allow them. You can deny everything and selectively allow.

Little Snitch

Protects your privacy and prevents your private data from being sent out to the Internet without your knowledge.

www.obdev.at

 

[Sal Collaziano]

Perhaps you should be approaching the problem differently. A firewall such as Little Snitch will stop any connections unless you explicitly allow them. You can deny everything and selectively allow.

Little Snitch

Protects your privacy and prevents your private data from being sent out to the Internet without your knowledge.

www.obdev.at

I do have security software installed but my concern is zero day exploits and things like that - which may not get picked up right away. I think what I have does something similar to Little Snitch already... I'm probably over-thinking all of this but my intention is to be ahead of the curve - and if having a separate computer for email only can be easy and fairly seamless - that's what I'm thinking I'll do... But I'm here learning...

 

[ignatius345]

There is so much craziness going on with viruses and malware that I'm beginning to feel it's best to have one computer specifically for email, and another computer - for everything else. My intention is to wall-off email entirely from my main computer.

Email is not the only vector of attack. You should also isolate your "everything else" machine from Messages and other internet services as well, right?

This all honestly seems like overkill to me, unless you're some kind of high-value target. And if you are, I'd suggest Lockdown Mode as a more comprehensive solution if you're that concerned about security threats.

 

[Bigwaff]

I do have security software installed but my concern is zero day exploits and things like that - which may not get picked up right away. I think what I have does something similar to Little Snitch already... I'm probably over-thinking all of this but my intention is to be ahead of the curve - and if having a separate computer for email only can be easy and fairly seamless - that's what I'm thinking I'll do... But I'm here learning...

The hypothetical "zero day exploits" need to be delivered somehow and will need to connect back to command server (after all, what good is a zero day exploit if not to exfiltrate data). Little Snitch will block the connection -- both delivery and exfiltration. You will have oppty to review. Allow / deny connection. Also, it's unlikely you will be target of zero day exploit, so I do think you are "over-thinking all of this".

 

[Sal Collaziano]

Email is not the only vector of attack. You should also isolate your "everything else" machine from Messages and other internet services as well, right?

This all honestly seems like overkill to me, unless you're some kind of high-value target. And if you are, I'd suggest Lockdown Mode as a more comprehensive solution if you're that concerned about security threats.

It probably IS overkill... I'll look into Lockdown Mode just so I'm aware of what it is and does.

The hypothetical "zero day exploits" need to be delivered somehow and will need to connect back to command server (after all, what good is a zero day exploit if not to exfiltrate data). Little Snitch will block the connection -- both delivery and exfiltration. You will have oppty to review. Allow / deny connection. Also, it's unlikely you will be target of zero day exploit, so I do think you are "over-thinking all of this".

I probably AM over-thinking... For me, this discussion has helped by bringing various items into sight. I will make considerations based on it.

 

[BeatCrazy]

There is so much craziness going on with viruses and malware that I'm beginning to feel it's best to have one computer specifically for email, and another computer - for everything else. My intention is to wall-off email entirely from my main computer.

I have seen this discussion - but it appears that person isn't using both computers simultaneously.

I have a 2017 iMac that I'm outgrowing and will probably replace it with a new Mac Mini Pro. I was trying to figure out what to do with the iMac's 27" inch monitor as it seems there's really no great solution to use it with a Mac Mini. I know solutions exist, but they don't sound too great to me.

So I'm thinking I'll just leave ALL my email (a lot) duties for the iMac and setup the Mac Mini Pro to handle everything else.

I'm just not sure how to use both the keyboard and mouse simultaneously with each computer. I use an Apple Magic Keyboard and a wired USB mouse.

Any suggestions?

I would check into using one of those 5K retina monitor retrofit kits. There are threads about it here. Just stop using the iMac as a computer and convert it to a basic monitor.

 

[Sal Collaziano]

I would check into using one of those 5K retina monitor retrofit kits. There are threads about it here. Just stop using the iMac as a computer and convert it to a basic monitor.

I will look into that.

 

[BeatCrazy]

I will look into that.

DIY 5k Monitor - success :-)

My "latest Macs" are a heavily upgraded 2009 Mac Pro (6c CPU, M.2 SSD, USB 3, RX580...) and more recently a 12c 2013 Mac Pro with an eGPU (Vega 56) - both machines with more than enough CPU power, GPU power and RAM for my needs, but I long aspired to upgrade to a nice 5k monitor to replace my...

forums.macrumors.com

 

[Sal Collaziano]

DIY 5k Monitor - success :-)

My "latest Macs" are a heavily upgraded 2009 Mac Pro (6c CPU, M.2 SSD, USB 3, RX580...) and more recently a 12c 2013 Mac Pro with an eGPU (Vega 56) - both machines with more than enough CPU power, GPU power and RAM for my needs, but I long aspired to upgrade to a nice 5k monitor to replace my...

forums.macrumors.com

Thank you.

 

[cateye]

People always assume the strangest, most complex vectors for attack.

The most likely scenario for you to fall victim to a scam is through social engineering. Put yourself in the shoes of a bad actor: Why rely on complex malware when people will just hand over their information freely? Clicking through on an expertly-crafted email that looks like it's from your bank or from Apple or from PayPal or whatever other trusted organization you want to imagine and haplessly giving up credentials or other personal information that allow the bad actor to escalate the ruse and start accessing your data or assets.

It's happened to a member of my family, it's happened to people I know, and it's something that no virus software, no firewall, no second computer will ever solve. Security requires knowledge, effort, and constant awareness. Is having a separate computer for email a bad idea? No, probably not. Organizationally, it might be kind of nice. But doesn't really solve much, security-wise. Having a false sense of security because of that construct, however, could do more harm than good.

 

[chown33]

You could turn on Screen Sharing on the iMac, then connect to it from the new Mac mini.

Share the screen of another Mac

On your Mac, use the Screen Sharing app to view and control the screen of another Mac on your network.

support.apple.com

You can setup the remote iMac ahead of time with a constrained user account, for example, only allowed to run Mail.app and Finder.

The remote iMac will appear in a window on the mini, which you can expand to full screen if desired. You can also Hide that window, and the remote iMac will effectively disappear.

I think Screen Sharing is less coupled than Universal Control. For example, if you wanted to copy files between the Macs, I think you'd also need to enable File Sharing on the iMac, then connect to it in Finder using Connect to Server.

Set up file sharing on Mac

Share the files and folders on your Mac with others on your network. Share your entire Mac or allow specific users access to certain folders.

support.apple.com

Also, Universal Control needs both Macs signed into the same Apple Account (AppleID), while Screen Sharing and File Sharing don't. If the goal is to isolate things, a shared AppleID is extra coupling.

 

[jakey rolling]

Clicking one button isn't really that big of a deal - so this could work... It would be nice, however, if the system knew to activate the keyboard on whichever screen/computer the mouse was currently using...

If you use one of the newer models of Logitech keyboards and mice that support multiple devices, you can use Logitech Flow to accomplish exactly this. Similar to the Universal Control that others have suggested here, Flow will detect when you're mousing past the edge of the screen of one computer and automatically switch your mouse and keyboard to the other computer.

The slight difference with Flow is that your keyboard and mouse are always directly controlling whichever computer your cursor is on, rather than sending the input data from a host computer over a network connection to the client computer(s). It is also compatible between Macs and PCs (if you want to also bring a PC into the mix).

 

[Sal Collaziano]

People always assume the strangest, most complex vectors for attack.

The most likely scenario for you to fall victim to a scam is through social engineering. Put yourself in the shoes of a bad actor: Why rely on complex malware when people will just hand over their information freely? Clicking through on an expertly-crafted email that looks like it's from your bank or from Apple or from PayPal or whatever other trusted organization you want to imagine and haplessly giving up credentials or other personal information that allow the bad actor to escalate the ruse and start accessing your data or assets.

It's happened to a member of my family, it's happened to people I know, and it's something that no virus software, no firewall, no second computer will ever solve. Security requires knowledge, effort, and constant awareness. Is having a separate computer for email a bad idea? No, probably not. Organizationally, it might be kind of nice. But doesn't really solve much, security-wise. Having a false sense of security because of that construct, however, could do more harm than good.

Yes, very true. For me, whenever I visit a link in an email. I copy the URL and re-enter the domain name - to be sure I'm actually going to the correct server/website. Things are getting really scary out there...

You could turn on Screen Sharing on the iMac, then connect to it from the new Mac mini.

Share the screen of another Mac

On your Mac, use the Screen Sharing app to view and control the screen of another Mac on your network.

support.apple.com

You can setup the remote iMac ahead of time with a constrained user account, for example, only allowed to run Mail.app and Finder.

The remote iMac will appear in a window on the mini, which you can expand to full screen if desired. You can also Hide that window, and the remote iMac will effectively disappear.

I think Screen Sharing is less coupled than Universal Control. For example, if you wanted to copy files between the Macs, I think you'd also need to enable File Sharing on the iMac, then connect to it in Finder using Connect to Server.

Set up file sharing on Mac

Share the files and folders on your Mac with others on your network. Share your entire Mac or allow specific users access to certain folders.

support.apple.com

Also, Universal Control needs both Macs signed into the same Apple Account (AppleID), while Screen Sharing and File Sharing don't. If the goal is to isolate things, a shared AppleID is extra coupling.

Thank you. Adding this to my notes...

If you use one of the newer models of Logitech keyboards and mice that support multiple devices, you can use Logitech Flow to accomplish exactly this. Similar to the Universal Control that others have suggested here, Flow will detect when you're mousing past the edge of the screen of one computer and automatically switch your mouse and keyboard to the other computer.

The slight difference with Flow is that your keyboard and mouse are always directly controlling whichever computer your cursor is on, rather than sending the input data from a host computer over a network connection to the client computer(s). It is also compatible between Macs and PCs (if you want to also bring a PC into the mix).

This almost makes it sound too easy. I will look into this...

 

[JtheLemur]

Don’t know who OP is but if they’re looking for security advice here, they seriously don’t need Lockdown mode, of all things. Fire up LittleSnitch, install any number of third-party malware tools, and chill out.

OP might want to seek a different kind of help. Either a professional security audit, or perhaps help with anxiety. (Seriously, not being an ass.)

If you want to be secure, air gap your gear. It’s the only way to be sure. (Mostly.)

 

[bettywilsonknd6689]

i do not think you can do it as easy as you wanted