Synology Container update using Backup

Installation
1

Solved :slight_smile:

I have a Synology using Container. The version I have now is 2025.8 and want to update to the latest version.

I am downloading the latest version in DSM under Container-Image. Hereafter I create the Container using the new Image and using my backup, but I get and error every time, that there is an Unknown error occurred. I have tried with the latest image and version 2025.9.0.

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I have also tried to create a new Container and hereafter try to upload my backup I will lose the connection during the process “Connection lost. Reconnecting…”.

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What to do, starting from scratch will take many days - and tears :slight_smile:

2

Check the docker/container logs for hints. What browser do you use? How large is the backup?

3

There is another post on upgrading to 2026.3 and docker failure. If not on DSM 7.2 then your docker version is likely too old and you need a fix.I managed to upgrade syno to the newer docker but this was not 1-2-3

Not sure if this is the same but worth a check,

2026.3 - Container Update Fails - Installation - Home Assistant Community

4

Thanks for the replay.
I have now found out what the issue was.

I made a backup with the History and it made me a backup with the size 3,09 GB and that was too large for my system.
When making a backup without History the size then was 0,49 GB and when using this backup, I was able to create a container from the backup.
Hereafter I open the system/backup and saw the full backup in the Synology DSM area. I did now make a backup from that and now it seems that I also have the history.

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