It's crazy that they did away with this feature. I figured out a solution that fixes this issue, and finally gives me back "All My Files." (I'm running Mojave 10.14.6). I assume this will need to be done with each update (thanks Apple!).
Here are the instructions:
This process requires temporarily disabling the SIP (System Integrity Protection) using the recovery terminal app… To do so, restart your mac, hold command+R, then select "Utilities > Terminal". Type: 'csrutil disable’ and press enter. Then restart your mac normally.
Step 1:
Create a saved search copy of "Recents" by navigating to Recents... then click the actions gear, and select “Show search criteria”. Use the following criteria in place of the existing raw query:
((kMDItemContentTypeTree = public.content) || (kMDItemContentTypeTree = "com.microsoft.*"cdw) || (kMDItemContentTypeTree = public.archive))
Save the search as: search.savedSearch (and save it to your desktop or another easy to find location).
Step 2:
Navigate to:
System > Library > Core Services > Finder.app (note: you need to right click, and select show package contents) > Contents > Resources > MyLibraries
Step 3: Copy “Recents” to the desktop or documents folder.
Step 4: Right-click the copied “Recents” package and select “Show Package Contents.” Now, remember the saved search you created in step 1? Okay, good… copy and paste it into the “Resources” folder inside of the Recents package contents.
Step 5: Copy the updated “Recents” package into: System > Library > Core Services > Finder.app (note: you need to right click, and select show package contents) > Contents > Resources > MyLibraries
You will be asked to authenticate as a system admin. Type your login password.
Viola! “All My Files” is back in action.
IMPORTANT! Now you need to re-enable the SIP (System Integrity Protection) utility: Restart your mac, hold command+R, then open terminal again and type: 'csrutil enable' and press enter. Then restart normally.
Now you can open a new tab and get Recents which are truly, well... recent.
Cheers,
Carter