Some pdf file names apparently corrupted, only an issue for iOS devices.

Question

I am having a weird pdf file name issue that is reproducible on both of my iPad devices. This is not a problem on my Android phone, or on my windows pc. It only affects a small number of pdfs which I have had no trouble downloading, opening, importing, resaving, attaching to emails for weeks. This issue appeared suddenly and with no apparent cause.

I can preview the files in the Dropbox iOS app, but when I try to attach one of the affected pdfs to an email in outlook, or if I try to download it from the iOS Files app, I get an error message:

This is obviously not the actual file name. Each affected file has a unique erroneous file name, and it is the same for each file respectively between both of my iPads.

I have tried:

* Deleting and reinstalling the Dropbox app
* Deleting and reinstalling the Files app
* Removing Dropbox from the file locations in the Files app, and then adding it back
* Renaming the file(s)
* I actually can save the files to my iPad device front the Dropbox app and they become usable, but when I save them back to the Dropbox folder, even with a different name, the same thing happens
* Duplicating them in the Dropbox folder on my pc

It seems there is something about these files that has messed up the way iOS is reading the file names. No idea what to look at next. Really hoping I can figure this out soon. If not the cause then at least a way to resolve it. These files are essential to projects I am currently managing and I use my iPads to work with them a lot.

Jay · Answer

Thanks for the update, in general, file names should follow these requirements to ensure full compatibility with all OSes and devices, so it's possible that there may have been something incompatible there.

Meyerbenr · Answer

Hi @Jay, thanks for your reply.

I didn't get any errors when uploading to Dropbox, only when attempting to download these specific files using the iOS Files app or attaching them to an email with the iOS Outlook app.

I spent some time on the phone with apple support before posting this question. They thought it could be an issue/corruption with the file name hash string between Dropbox and iOS.

I haven't been able to replicate the issue on other files, but I was able to resolve it with the (4) that were/are affected by removing all of the spaces in the names.

An example:
20230419 - 22 - 015 - ClientName - Client City - CDs - ARCH - REV1
Became
20230419_22-015_ClientName_CC_CDs_ARCH_REV1

I'm not really sure why this worked. One of the affected files had a way shorter name to begin with. I thought maybe the overall file path was a factor in the name length but ruled that out by dropping an unaffected file with a similar name into a test folder in the folder where 3 of the affected files were and it was still fine.

I'm stumped. It's not ideal that these file names no longer match our naming convention, but it's not that bad. At least I can access and work with them on my iPads again. If I discover how to replicate the issue I will be back!

Thanks again.

Jay · Answer

Hi @Meyerbenr, thanks for bringing this to our attention.

It could be an issue with the way the iOS Files app is attempting to access the PDF file on Dropbox.

As you mentioned you were able to download from the Dropbox mobile app with no issue, what error did you get when uploading to the Dropbox mobile app?

This will help me to assist further!