Slate AX HDD file sharing issue, works but not all files shown

When I have a 5tb hard drive plugged into my Slate AX it only shows about 2/3rds of my files. This is on a Mac. On my App it does show the missing files. I have tried this unpowered and with a powered USB hub. I have also tried this with a 1tb SSD.

5TB I ex-fat, I have tried the SSD with both ex-fat and fat 32

Also if I try to copy a file to the drives it is unable to do it and gives me a -50 error.

I tried to do a search for an answer in the manual, forums etc, but I don’t seem to be able to find one as this is only a secondary feature.

I purposely chose the AX over the Plus as it had a larger power supply. Seems it wasn’t really worth the extra expense.

What is your hard drive model?
How much capacity does LuCI → System → Mounts show after inserting the drive?
Is it easy for you to change the format of the drive to try? For example ext.

Sounds like a permissions issue. Are you using samba?