keyerror 1

I raised this bug as soon as the message appeared, "preserving the scene" .
I suspect the issue is simply due to group (/etc/groups) changes. The user lacked permission to mount the SD cards, then mount by the file-manager had some kind of timeout so the directories, in effect, disappeared .

Before you dismiss this as simply "not a bug" , I'd suggest you address the "cry wolf" issue.
I was asked to raise a bug, when the error should probably have been something like "no permission to read xxxx ... have you unmounted/unplugged the device?" If you want people to raise defects when an issue occurs, rather than simply ignoring them it would help if they don't get many false negatives.

First, update the program to the latest version. The version you are using is really old. The bug may have been fixed in a more recent version. https://damonlynch.net/rapid/download.html

Second, I don't know why you are assuming how I would handle this bug report. I don't recall that we have ever interacted before. It's not pleasant to read a statement like 'Before you dismiss this as simply "not a bug" , I'd suggest you address the "cry wolf" issue'. Please do not do that.

>It's not pleasant to read a statement

Apologies if the language jars, not intended, cultural differences I suspect.

So the sequence was:

1: I get a pop up with an error message
2: The message asks me for forward the information (as a bug report)
3: I attempt to be a "good citizen" and forward the information as requested

4: after "moving on" it seems clear to me the issue is probably a result of "something else" (e.g a file-manager) unmounting the device ... seems pointless for the dev to waste time debugging a non-existent issue, so I follow up with a comment

5: However the incident is not without some "usability value" if end users are constantly asked to collect debug info for issues that are not bugs and won't be investigated, they will tend to stop doing so and we'll all end up with "less good software" . So the "lessons learned" I take from this is things like files not found, unreadable , probably just warrant a "can't read xxx type message" .

To be clear, I had no problems with the software, I was happy just to remount and redo , the only reason I raised the report was because I was being asked to do so.

This website only appear to allow one attachment , so I was unable to attach this screenshot. (now attached)

As you see I was asked to "report the problem" ... this was the "cry wolf" I referenced ...possibly a little strong, again apologies for offence caused.