# "Image not found on registry" error when upgrading from CE to BE or self-updating on Synology NAS

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**Affected versions:** 2.17.0 and above
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#### Issue Description

When running an in-app upgrade within Portainer that is running on a Synology NAS, users may receive an error "Image not found on registry".

#### Cause

Our team is currently investigating the cause of this issue, but we suspect this is a consequence of Synology's custom Docker build.

#### Workaround

The workaround for this is to follow the legacy upgrade steps found in the [Portainer documentation](https://docs.portainer.io/2.33-lts/start/upgrade) and follow the manual steps option for your environment. This will guide you through the steps to update your Portainer install.

Some users have also reported success with [manually pulling](https://docs.portainer.io/2.33-lts/user/docker/images/pull) the missing image first, then attempting the in-app upgrade.

You can find more details on this issue in the [GitHub Issue](https://github.com/portainer/portainer/issues/8590).