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Thunderbird suddenly got slow after upgrading to Windows 10 which keeps setting process priority to "background"

Patrick Larkin
Patrick Larkin
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I've been using TBird for years. My company was on Windows 7, but recently upgraded us to Win10. I've noticed TBird getting slower and slower and in the past day it has gotten to where I could only type a word in compose windows before it froze, clocked, and said "Not Responding".

In the process of trying to find out why, I noticed in Process Explorer that the priority of TBird keeps getting pushed down to Background (4) vs "Normal" (8). Even if I set it to 'Above Normal' (10), it eventually gets pushed back down again.

(version 10.8.0 32-bit

I've been using TBird for years. My company was on Windows 7, but recently upgraded us to Win10. I've noticed TBird getting slower and slower and in the past day it has gotten to where I could only type a word in compose windows before it froze, clocked, and said "Not Responding". In the process of trying to find out why, I noticed in Process Explorer that the priority of TBird keeps getting pushed down to Background (4) vs "Normal" (8). Even if I set it to 'Above Normal' (10), it eventually gets pushed back down again. (version 10.8.0 32-bit
Attached screenshots

Chosen solution

I doubt it's a W7 vs. W10 issue, but it could be due to a different security program on the two OSes. How is the performance of TB when you run in W10 safe mode?

https://wiki.mozilla.org/Thunderbird:Testing:Memory_Usage_Problems

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sfhowes
sfhowes
  • Top 10 Contributor
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Chosen Solution

I doubt it's a W7 vs. W10 issue, but it could be due to a different security program on the two OSes. How is the performance of TB when you run in W10 safe mode?

https://wiki.mozilla.org/Thunderbird:Testing:Memory_Usage_Problems

Patrick Larkin
Patrick Larkin Question owner
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I systematically disabled all add-ons until the issue went away. Then I removed the files it was using, and re-enabled the add-on (which created fresh new files). I've since taken the issue to the Add-on developers.

I still don't understand what mechanism was changing the process priority. Ah well, Windows. :D