Collection was modified; enumeration operation may not execute

[Opus132]

I just erased my MAME rom set and was trying to import it again, but at the end i get this error: 

I tried to google this error in relation to launchbox and the only thread i found mentioned to turn off the auto-import feature, but i had already done that a while ago. 

Is it because i kept some games in the collection (i have a couple of games i imported manually from a different source because they were stripped out of MAME, like Akai Katana and a few others). 

Of course i also tried to import them in a different platform (i called it Arcade [ALT]) but i got the same error there as well. Not even sure if it's possible to have alternative versions of the same platform, but i guess it was worth a try. 

I restored my backup but now it seems i'm stuck with what i imported originally, and i have imported way too many platforms and systems already to start over with a fresh install of launchbox (i just tried and that works fine). 

Edited April 23 by Opus132

[Opus132]

Ok, so i tried erasing every trace of the platform, but i get the same error. 

Seems i'm now permanently barred from importing MAME roms. What could cause this? The tool works fine with a freshly downloaded version of launchbox but again i can't start over rebuilding my collection. 

 

[C-Beats]

Turn on debug logs via LaunchBox Options window and then try it. Let it fail and then close the app and look for the most recent file in \\LaunchBox\Logs and look in there to see if an error is mentioned in there that may help.

[Opus132]

To be honest i can't see anything explicit, just lot's of "null" references. I attached the log file all the same.

Debug 2025-04-24 04-16-21 PM.log

[C-Beats]

Yeah, looks like you definitely have something going on in your data files

[C-Beats]

Can you throw your \\LaunchBox\Data\ folder into a zip file and PM me with it here on the forums? I can try and take a look and see if anything obvious stands out as wrong.

[Opus132]

Well, what do you know. While i was preparing to zip the data folder, i noticed there was a parents_temp.xml file with zero bytes which i hadn't noticed before. I figured maybe that was it and low and behold, after erasing it now the MAME importer works again. 

No idea where that file came from i guess it was created on a crash and then got picked up by the autoback up utility so every time i tried to "restore" some previous back up the file got put in there again.  

[C-Beats]

Glad you got it sorted, thanks for the update!