Pathes to sync folders Windows and OSAOS

SyncThing works if: 1. the path on my Zimaboard is /DATA/AppData/syncthing/config/Sync, and the path on my Windows machine is C:\Users<user>\Default Folder (~\Default Folder). No luck when trying to sync between /mnt/8TB/Sync and E:\Documents. 8TB is a WD 8TB hard drive (Blue) and E:\Documents points to a 2nd SSD. I first copied E:\Documents to the 8TB using Microsoft’s SyncToy 2.1 and then tried to set up Syncthing to sync between E:\Documents and /mnt/8TB/Sync, no luck. I must be doing something wrong? Any advice? My goal was to have all files from the 4 devices on my home network loaded on 8TB for home cloud sharing. I can achieve mostly what I wanted to do with SyncToy, but is a little cumbersome.

Based on your description, most likely an issue with file permissions, so verify that whichever user Syncthing is running under has read/write permissions on /mnt/8TB/Sync. Same goes for E:\Documents.

What’s missing in the details above are how Syncthing is installed on the Zimaboard (e.g. Linux?, Android?, Docker?,…) and on Windows (e.g. official Syncthing package or 3rd-party wrapper?). And what filesystem is on /mnt/8TB?