Changing files on SD card mostly fails

I'm setting up an SD card with a ton of games and music files to be used on my 'new' Commodore 64 computer. I've downloaded a couple game and music archives, so the total file count on the SD card is around 80,000.

One of the quirks of the Commodore 64 is that it cannot elegantly display uppercase characters in filenames - they get incorrectly displayed as "PETSCII" characters, which makes browsing the files on the card quite challenging. The "easy" solution is to only have lower-case filenames, but with nearly 80,000 files, that becomes slightly more challenging.

I fired up Advanced Renamer (fully paid/registered, fully up to date) and started selecting batches of subfolders to keep under the 25,000 file limit. I have the Batch Method set to New Case > Set Lower Case, and when I review the Filename vs. New Filename columns, everything looks correct. However, when I hit Start Batch, it seems to go through all the motions, but only some content actually gets renamed - some folders, a few random files within, but it's mostly not working. There are no reported errors.

It occurred to me that the amount of time it's taking to "complete" the batch seems suspiciously fast, given how long it takes to read or write tens of thousands of files on an SD card. I made a full copy and paste of the SD card contents into a subfolder on a very fast internal SSD and tried applying my changes there, and got a better (but still not correct) result - many subfolders and files are now lowercase, but not all of them.

Any tips on what I'm doing wrong here would be appreciated!

Reply to #1:
Sounds like an interesting project. The Commodore 64 was my first computer and the first computer I learned how to code on.

Working with SD cards can be tricky. They are mostly slow and they can have hardware specs and formatting that makes them unpredictable in certain scenarios.

The best solution is to copy all the files to a local drive and perform the batch there. It works much better and faster. But it sounds like you already did that. Performing this type of batch should work without any errors and with all files renamed. I don't know why some files are skipped.

Have you tried including all files in one single batch? You can change the limit from 25.000 to 100.000 in the settings windows.