Unable to save workflow.

You might want to read these entries to learn about your 3 locations of KNIME data.

You could (and maybe should) im- and export your workflows or group of workflows to save or share your work. If you want you could also include full data and the latest status but that would cost disk space:

https://docs.knime.com/2020-07/analytics_platform_quickstart_guide/index.html#useful-tips