Fixing mega-sync "Failed to sync folder: Invalid argument" on Ubuntu Containers

Sat, 28 Mar 2026 10:00:00 +0000

When mega-sync fails with the following message:

Failed to sync folder: Invalid argument. Unable to retrieve the ID of current device

the problem is often not the sync path itself. In my case, the real issue was that the Ubuntu environment deployed inside Docker did not have a valid machine ID.

Why This Happens

MEGA relies on the current device ID when creating or managing sync relationships. On some minimal Ubuntu container images, /etc/machine-id can be missing or empty. When that happens, mega-sync cannot identify the current device correctly and returns the misleading Invalid argument error.

How to enter QNAP NAS Mega CMD

Sat, 11 Mar 2023 23:19:05 +0000

Mega CMD is an software that provide similar function of QNAP HBS, but I don’t know why they can’t just integrated their function into HBS. And it is a command line system, though I’m not afraid of command but it truly increase the inconvenience for those who just want to make a backup. Most seriously, the way to enter the cmd window won’t show up on their readme.md but only in the introduction of the app store, with an very blurry picture. That’s ridiculous. I hope they can make the doc clearer in the future.

Mega on Mr.W's Blog

Fixing mega-sync "Failed to sync folder: Invalid argument" on Ubuntu Containers

Why This Happens

How to enter QNAP NAS Mega CMD