After trawling through logs last night I eventually found this -
Doctrine\DBAL\Exception\UniqueConstraintViolationException: An exception occurred while executing 'INSERT INTOoc_file_locks
) SELECT ?,?,? FROMoc_file_locks
= ? HAVING COUNT(*) = 0' with params ["files\/c43fefb2658bed7562aaa2fcc61bb210", 1, 1512521839, "files\/c43fefb2658bed7562aaa2fcc61bb210"]: SQLSTATE: Integrity constraint violation: 1062 Duplicate entry 'files/c43fefb2658bed7562aaa2fcc61bb210' for key 'lock_key_index'
Which looks like the record relating to the file exists in the db but the directory and file do not physically exist. Too late and too tired to attempt to fix last night.
I guess all that we need to do is remove these entries from the table??
@thealce can you log into the web client, click admin from the menu, then logging. Do you see any messages there when trying to upload?