Desktop App Crashing on XFCE when Syncing to External Drive

I am running Linux Mint 22.1 with XFCE. The desktop app (whether the appimage from the nextcloud site 4.0.x or the repo version 3.11.0) crashes whenever I begin syncing to the new external drive on the client side I need to sync to.

Somethings to note:

-this worked on the same drive last year, but after my raspberry pi server died, I took a while to setup anew

-it worked initially and synced but then crashed and despite purging everything (not data) and restarting it consistently crashes immediately when I attempt to sync there

-it will, however, sync a small test file elsewhere, but not on the external drive (despite initially and previously syncing there with no change to settings).

I must sync to external due to limited SSD size. Help?

To which of both devices the external drive is connected? Not clear what you have connected to what. Is the external drive connected to Mint 22.1 or raspberry pi server?

Sorry:

Pi is nextcloud server (also with external hard drive)

Mint 22.1 laptop is a client connected to external drive that now (but not previously) crashes as soon as syncing nextcloud to the external drive.

Define “crash”. What specifically happens?

It locks up, won’t respond, and needs to be killed to exit the app.