Where besides BizFormFiles would a file uploaded as part of a file submission be found?

Typically they are stored in <root>/<sitecodename>/files in no particular order. They use the first 2 characters of the GUID for the file to place it in a folder.

Unfortunately, it's not there. This is a BizForm file uploaded as part of a form submission. From the form response I get the link:

https://sitename.com/CMSPages/GetBizFormFile.aspx?filename=<some GUID>.pdf&sitename=sitename

That link works, but when you search anywhere in \CMS\ for that GUID, nothing comes up. I know that page attachments under workflow get moved to CMS\App_Data\VersionHistory, is something similar happening here?

This instance did once have all files stored in the database, but then I changed that setting and moved page attachment binary data out of the database and onto the filesystem via a custom module I wrote. Are form files ever stored in the database?

You can also check in the <root>/CMSFiles directory. If it's not there, then check to see if you're storing your filed in the database. If so, then those files are not available in the file system.

What db table would hold that data? I might need to migrate it out of the db.

You can go to the System > Files > Attachments and you may find your attachments in there. You can force the attachments in the database to be stored in the file system.

I would check whether there is not a custom folder set for the form files - link to documentation.

Juraj,

There isn't a custom folder set. And the file I'm looking for was uploaded through a form, not a page attachment. All I want to know are the places a form file could be. In other words, what's the algorithm for resolving a form file link? Where does the CMS look under what conditions?

I only know one place to look and I can't find this file. I need to know because I am planning to move all those files to a custom folder because we have ~170GB of content files mixed in with our application files and it makes CI and development a nightmare. If I'm missing this file, I'm likely missing others.

I sent you link to the documentation since also describes where the form files are stored by default: "Files uploaded by website users into forms are always stored in the file system. The default location is ~/< site code name >/BizFormFiles. You can customize the location in Settings -> System -> Files -> Custom form files folder."

Since you could not find it, I thought there could be some custom folder set.
In the link, there is the getbizformfile handler (~/CMSPages/GetBizFormFile.aspx?filename=< some GUID > .extension), which is looking on the disk into the default or custom form files folder and looks for the file's GUID as this is used as the file name.