i cannot update my system.
F2-220
TOS 5.1.131-00123
2 1TB HDD mounted as RAID 1 (290GB free space)
When I try, i receive the error in the image.

How can I solve this?
There has always been a possibility that updating to 5.1 might work initially but there was always the likelihood it would fail eventually. {Basically when needed system space is not available}. Unfortunately users continue to update either without reading about the restrictions (in the Update Notices) or simply ignoring them. Then, those users moan about the failure and @TMSupport (and other users) would have to step in, repeat the explanations and warnings, and try to help the user with system recovery.
To be fair, there may also be numerous users who just do know about this forum. No one can assume every user comes here to read before hitting the update button. Generally for most devices it is recommended to always update to latest available software to avoid vulnerabilities.

But see, Terramasters are special, they are not like "most" devices.
To prevent users who do not meet the update requirements from pressing the update button without understanding the update requirements, which may lead to device failures, the recent version of TOS 5.1 and the update notification for TOS 6 will only be posted on Terramaster's forum to ensure that users understand the update requirements before updating.topo01 wrote: ↑22 Jul 2024, 02:09To be fair, there may also be numerous users who just do know about this forum. No one can assume every user comes here to read before hitting the update button. Generally for most devices it is recommended to always update to latest available software to avoid vulnerabilities.
With initial 5.1 releases some may have run into severe problems without any warning. I wouldn't call them all "ignorant".
As I already suggested: The update warnings and descriptions of preconditions should also appear in the control panels update section. It could even be combined with a handy forum link. That would be helpful for many "ignorant" users.
