"cannot shrink the filesystem" (not system partition - just data)

[prosef]

I had an existing, encrypted data-only partition. I needed to shrink slightly (to make room for a different partition), so I decrypted it in-place, then resized it. Now I'm trying to re-encrypt it in-place. Whenever I try, Veracrypt says "cannot shrink the filesystem" (to make space for the volume header).

• The first suggestion it gives is to make sure there's enough free space. There's more than 150 gigs free.
• The second suggestion it gives is to run scandisk. Scandisk reports no errors.
• This thread suggests checking the Windows Event Viewer for details on the error. I can't find anything there (which category should it be under in the Event Viewer?): https://sourceforge.net/p/veracrypt/discussion/technical/thread/968069cc/?limit=25#eab6
• This thread suggests defragging. I think that's not relevant for SSDs, but I tried anyway (it took like 30 seconds in total). The error message persists: https://sourceforge.net/p/veracrypt/discussion/technical/thread/e4a3053c/?limit=25&page=1
• This post has the same issue, but no solution: https://superuser.com/questions/1505705/cant-encrypt-a-non-system-drive-in-place-with-veracrypt
• The remaining solution given by VeraCrypt is to basically create a whole separate encrypted partition, and copy the data back and forth. It's 4TB of data - besides being impractically slow, I don't have another 4TB of local storage laying around (my personal backups are on a remote NAS).

How can I get this re-encrypted, like it was just yesterday? I really wish I hadn't decrypted it, now I can't figure out how to get back to where I was....

[Enigma2Illusion]

User solved problem by shrinking using Windows Disk Management instead of gparted.

https://github.com/veracrypt/VeraCrypt/issues/1423#issuecomment-2380051670