I’m dual-booting my machine right now with CachyOS linux and Windows 10. A have a few VeraCrypt volumes originally created on Windows on an NTFS formatted disk that I’m trying to use and I’m having issues with one in linux.
One volume when it’s mounted in VeraCrypt isn’t writable (4.9TB volume) and the other is (3.0TB). Both volumes reside on the same physical disk and in the same directory. The disk they resides on is writable and my user has read, write and execute enabled on both volume files and the mount directory. If I try to copy a file to the 4.9TB volume however I get a message that it’s a read-only file system. Checking the volume properties in Dolphin it shows it’s writable though.
Output from mount does suggest it’s mounted read-only though. Here you can see the difference between the two volumes, 1 and 2:
veracrypt on /tmp/.veracrypt_aux_mnt1 type fuse.veracrypt (rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other)
/dev/mapper/veracrypt1 on /run/media/veracrypt1 type ntfs (ro,relatime,uid=1000,gid=1000,dmask=0077,fmask=0077,iocharset=utf8)
veracrypt on /tmp/.veracrypt_aux_mnt2 type fuse.veracrypt (rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other)
/dev/mapper/veracrypt2 on /run/media/veracrypt2 type exfat (rw,relatime,uid=1000,gid=1000,fmask=0077,dmask=0077,iocharset=utf8,errors=remount-ro)
So why exactly is VeraCrypt mounting it “ro” vs “rw” and is there anyway I can change that? Not sure if it matters but I’m using VeraCrypt version 1.26.24 on Linux, whereas on Windows I’m using 1.25.9.

Hmm, well I appreciate you considering my hypothesis. The last thing I would try is unmounting using the terminal (not GUI, as this will remove the underlying device) and then mounting that mapper device again in the terminal, to see if it gives me any messages about why it can’t satisfy a request to mount as writable.
Beyond this, and based on the available information, I am not sure.