Many files in SumatraPDFPortable\data\temp

Hello everyone
I use Sumatra PDF portable, and now I found out, that meanwhile I have about 32000 .tmp files in the folder “…\SumatraPDFPortable\Data\Temp”. What are the files needed for, or is it possible to delete them (automatically). Many thanks for help.
Greetings, Fred

Hi Fred
official SumatraPDF portable should not build \Data\Temp
I would ditch that rogue version and get a clean one from prerelease or older stable 3.1.2 then tell us if the official one does anything similar

Only 1 other source can be recognized as acceptable, and they have their own support at

Hi again
I installed this new (portable) version. It exists only from the one file.
My “old” version was “2.3.2”, and it had some subfolders,
Till now, no data/temp folder was created or any data stored in the new programm folder (except “ini-file”)
Thank you!

Here is what 2.3.2 Portable folder should have looked like and here is what the latest Portable folder should also look like after first run, there may a few others added by other versions such as needed when crash reporting or unpacking a comic book but I never saw \data\temp here


SumatraPDF 2.3.2 =4.84 MB (5,076,464 bytes)

The sumatrapdfcache is all those thumbnails (like1339ad261d62229b3f6ef92f6c82a6b3.PNG) for the first page of Your Top 10 favorite covers and over time if you read 32000 files there would be 32000 covers but only 10 are needed ? Those 32000 can safely be deleted as they will rebuild when you next open the Top 10 favorite files.

I first tried to put the new version in the old folder, but SumatraPDF did not remember were I was in the last PDF (always showed first page)
In the meantime I put the the new version in a new folder, and it looks like your screenshot above.
Now it works as expected.
The old folder with the data/temp… I already deleted.
Thanks again for your support!