I recently upgraded from KMyMoney 4 to 5. I now have a problem where 50% of the time when I directly import a bank statement via Firefox. KMyMoney closes.
I can download the same file to the hard drive and import it fine.
the following seems to happen.
Request Firefox to import the file to KMyMoney via the dialog box
A splash screen from KMyMoney comes up (this is normal)
Then the splash screen disappears. At this point normally you would see a small dialog at the bottom of the screen saying "Importing a statement via Web Connect"
Instead "Ready" is displayed and after 10-20 seconds KMyMoney closes with out saving.
I have enabled OFX logging, However a log file is not created when this occurs. (It normally is)
So 2 questions
Any ideas what is going wrong,
And how can I create a log file, or where would a log file be stored.

I have logged a bug but it is not a consistent fault and I need a log file.

Which version of KMyMoney are you using? Could be, that your version has a bug which was fixed in the meantime. You can try to use an up-to-date version on Linux using the AppImage version of KMyMoney in case your distro does not provide a newer version. Starting KMyMoney from a terminal window may provide additional information.