If the attachment file extension is capitalized, like .JPG instead of .jpg for example. 5.800 saves the those files as PICT3102.JPG.txt
Earlier version could understand that .JPG is picture (but wasn’t able to remember the program user wanted to use to open it, so it asked that every time).
And if there already exist a file under same name the automatic renaming renames the file as “PICT0001.jpg (1)” instead of “PICT0001 (1).jpg” so the picture apps can’t understand those are pictures.
About the file extension I’m not sure but the number for duplicate files is not added by K-9. It’s added by the System file manager, so there is nothing K-9 could do about it, unfortunately.
Earlier version of K-9 didn’t have that issue. Can’t test if now since Android apps can go only forward, not backwards. But with old version there wasn’t this kind of problem.
Yeah, in the old version K-9 stored the attachment itself by writing directly to the storage. Unfortunately, new Android versions no longer support that, so K-9 now just relays the file to the system file manager and asks it to save the file.
5.8 is trying to open .xls files as word docs.
When researching I saw this thread and thought it might be due to a previous file with the same name because if I download the file instead of opening it K9 stores it as .xls.doc.
I deleted all previous files with the same name but no joy.