Andre, thank you for your response.
The issue still exists when enabling the option “Create temporary decrypted files in the folder of the encrypted file”. The encrypted file resides on drive d: which is a conventional hard drive. When disabling the option again the temporary folder c:\Users<username>\AppData\Local\Temp" is used, which resides on a standard SSD.
As far as I can tell, there is nothing unusual with the drive containing the Temp folder and nothing unusual with drive d:. There is far more space available as needed on both drives.
But I found out something interesting:
When encrypting a huge “tar” file, decryption fails as described. When renaming the huge tar file to e.g. “xar” before encrytion, decryprion works fine. So - at a first gance - it seems as Kleopatra does not properly decrypt huge encrypted tar files.
In particular:
I encrypted a 36 Gb sized file named “basename.tar”. Encryption worked fine. On decryption a SUBFOLDER named “c:\Users<username>\AppData\Local\Temp\kleopatra-mlqSRk\basename.tar_1_” was created in the temporary folder which held no files. There was no sign that the decryption process would allocate any disk space. After a few minutes of decryption Kleopatra crashed as described. Enabling the option “Create temporary decrypted files in the folder of the encrypted file” does not prevent Kleopatra from crashing.
Then I simply renamed the 36 Gb sized file “basename.tar” to “basename.xar” and encrypted it. Encryption worked fine. On decryption a FILE named “c:\Users<username>\AppData\Local\Temp\kleopatra-amRdIQ\basename.xar.fwOLLL” was created in the temporary folder which increased in size as the decryption process proceeded. Decryption finished successfully.
So, it seems, Kleopatra behaves differently when decrypting encrypted (large) tar-files. As a workaround I now zip large tar files before encrypting it. Then, when decrypting, Kleopatra does the job well.
Another issue, which seems to be related:
I also encountered that Kleopatra tries to do an untar on decryption. For example: I have a small tar-File named “basename.tar” containing a folder named “XY” with some small files in “XY” and encrypt this tar file. The result is a encrypted file named “basename.tar.gpg”. When I decrypt this “basename.tar.gpg”, Kleopatra does not create a file named “basename.tar” as I would expect. But Kleopatra produces a new folder named “basename” containing the folder “XY” as well as the files of “XY”. So, Kleopatra obviously untared the tar file upon decrytion. I consider that this is the reason why Kleopatra crashes on the decryption of large tar files. Somehow it tries to untar it during the decryption process, but cannot fully untar it for reasons unknown to me and finally crashes. This does not happen with zipped or gzipped files. It seems to happen only with tarred files. And it also works on the command line, why I suspect to be a Kleopatra related issue.
This behaviour might be intentional, but but in my humble opinion it is highly confusing and not what I would expect Klkeopatra to do. Why would Kleopatra untar the tar files if I just want Kleopatra to decrypt it? Can this untarring be suppressed somehow?
Regards
Alex