WinMerge
Hard crash
I recently installed windows 11, and installed WinMerge to help verify that the files I transferred from my old computer to the new one matched the ones in a backup diectory, all on the new computer of course. apparently there were too many files, or something, because i was forced to select STOP. That completely froze my computer. I finally was forced to use CTL-ALT-DEL. i selected winmerge as the process i wanted to end, and hit end process. my computer screen went dark with a spinning circle that said "shutting down." I wouldn't shut down. i tried holding the power button and that didn't work either. i finally had to shut off the power to the computer. The computer booted up with no problem. In 35 years of running desktop computers I've never had to literally "pull the plug."
Thank you for the report, and I’m sorry for the trouble caused by the freeze.
Could you please provide some additional information to help us investigate?
- The WinMerge version you were using
- CPU core count
- Memory size (RAM)
- Approximate number of files in the compared folders
One possible explanation: In versions prior to WinMerge 2.16.52.2, the default number of CPU cores used for folder comparison was (number of CPU cores - 1). On systems with many cores, this could lead to very high CPU load and memory usage.
Starting from 2.16.52.2, the default has been changed to maximum 4 cores (the value can still be increased manually if needed).
As a workaround, please try reducing the “CPU cores to use” value in:
Options → Compare → Folder → CPU cores to use
For example, setting it to 1 or 2 may avoid system overload and improve stability.
Thank you for replying to my posting.
I have Version 2.16.52.2, X64 I just bought this new Dell computer with an Intel Ultra i7 having 20 cores, and 32GB of RAM. The size of the two folders being compared was obviously way too large; I think about 160 GB. I was trying to make sure that all of the files from my previous computer had been correctly copied over to this new machine.
I also did not understand how "OneDrive" works in this situation which meant that some of the files shown as "on my desktop" were actually still in the Onedrive cloud. So I thought the two folders were physically on my machine, but now I think that much of the data were actually in the cloud so it was having to retrieve the file to do the comparison. What a mess. No harm was done, thank goodness.
-john barrer
On Sun, Dec 7, 2025 at 4:34 AM Takashi Sawanaka @.***> wrote:
sdottaka left a comment (WinMerge/winmerge#3059) https://github.com/WinMerge/winmerge/issues/3059#issuecomment-3621859148
Thank you for the report, and I’m sorry for the trouble caused by the freeze.
Could you please provide some additional information to help us investigate?
- The WinMerge version you were using
- CPU core count
- Memory size (RAM)
- Approximate number of files in the compared folders
One possible explanation: In versions prior to WinMerge 2.16.52.2, the default number of CPU cores used for folder comparison was (number of CPU cores - 1). On systems with many cores, this could lead to very high CPU load and memory usage.
Starting from 2.16.52.2, the default has been changed to maximum 4 cores (the value can still be increased manually if needed).
As a workaround, please try reducing the “CPU cores to use” value in:
Options → Compare → Folder → CPU cores to use
For example, setting it to 1 or 2 may avoid system overload and improve stability. image.png (view on web) https://github.com/user-attachments/assets/9cfa7a28-fd97-4ec2-9c21-0bae6de911ad
— Reply to this email directly, view it on GitHub https://github.com/WinMerge/winmerge/issues/3059#issuecomment-3621859148, or unsubscribe https://github.com/notifications/unsubscribe-auth/B3FTFYOCNFHMRZLKGW3FM5D4APYBNAVCNFSM6AAAAACOH7PMJCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTMMRRHA2TSMJUHA . You are receiving this because you authored the thread.Message ID: @.***>
I see — the comparison was against a OneDrive folder. Using multiple cores may have triggered many simultaneous downloads, causing heavy system load.
Yes, I think something like that must have happened. I just switched from Windows 10 to 11 with this computer. I didn't use OneDrive (intentionally, at least) with WIN10. I didn't realize until too late that with win11 all my desktop files were not really on my hard drive; they are in the Onedrive cloud until you explicitly set them to reside on your machine. As Bill Gates would say, that's not a bug; it's a feature.
On Sun, Dec 7, 2025 at 4:33 PM Takashi Sawanaka @.***> wrote:
sdottaka left a comment (WinMerge/winmerge#3059) https://github.com/WinMerge/winmerge/issues/3059#issuecomment-3623460206
I see — the comparison was against a OneDrive folder. Using multiple cores may have triggered many simultaneous downloads, causing heavy system load.
— Reply to this email directly, view it on GitHub https://github.com/WinMerge/winmerge/issues/3059#issuecomment-3623460206, or unsubscribe https://github.com/notifications/unsubscribe-auth/B3FTFYJKO45SJAWZ7Y7A7J34ASMIZAVCNFSM6AAAAACOH7PMJCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTMMRTGQ3DAMRQGY . You are receiving this because you authored the thread.Message ID: @.***>