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Basic75

macrumors 68020
Original poster
May 17, 2011
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MacBook running Big Sur, Safari is shown as "Preventing Sleep" in Activity Monitor even with no tab open. Any ideas how to fix this?
 
Please paste this command into a Terminal window:
Code:
pmset -g assertions
Then copy and paste the output into a post here.

The output should list any assertions that are preventing sleep. If we know the name, then that can be entered as a search term with "Safari". This might be a more informative search result than just "why is safari preventing sleep".
 
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@chown33 Here's the output of pmset -g assertions and the ps(1) listing for the two mentioned PIDs. I don't understand why this UserEventAgent is now blocking sleep every time Safari is just opened, and it's weird that the PID of the supposedly "created for pid 606" process is smaller than 606. Perhaps Google can help...

pid 318(UserEventAgent): [0x00000139000b839b] 16:22:00 BackgroundTask named: "com.apple.safarishared.WBSParsecDSession.autoFillDataUpdate" Created for PID: 606.

user 606 2.3 2.1 10650164 352424 ?? S 3:43PM 4:09.88 /Applications/Safari.app/Contents/MacOS/Safari

user 318 0.0 0.1 4434184 13980 ?? S 3:41PM 0:05.24 /usr/libexec/UserEventAgent (Aqua)
 
I did several searches and didn't find anything too useful for either "WBSParsecDSession" or "autoFillDataUpdate".

Given the clue of "autoFill", I"d try turning off auto-fill entirely and see if that solves the problem. If it does, then at least the likely source of the problem is identified.
 
I noticed this too. Granted, I’m on a 5,1 with opencore and Big Sur, but with Safari open, it won’t sleep. Quit safari and it conks right out with the display. I can manually enter sleep via the menu, but it won’t do anything but suspend the display with Safari open.
 
So, what we've got in common is we're all three using Big Sur - and maybe all of us using Safari 16.x?
 
I'm on the latest version. Maybe a bug for x86 Mac users? I suspect the M1/M2 Macs don't suspend in the same fashion as the x86 versions. I think they have a lower power state that never truly sleeps by suspending to RAM.
 
And to make things more interesting, I just reopened Safari and the tabs I had going, then ran
pmset -g
in terminal and it's not saying anything is preventing sleep now. Now it's sleeping fine. Very odd.
 
Since my Mac is unsupported by Apple someone with a supported one should file a Safari bug report for this issue.
 
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