@supersharp there was a lengthy discussion that seemingly involved similar problems.
Execute failed: Cannot read file "knime_container_20200301_1905559478659870280.bin.snappy"
For @qqilihq one helpful step was to switch the internal compression to gzip. That would obviously only work after a restart.
If you have a workflow open and cannot save it these things come to my mind
- try opening a fresh WF and copy/paste the whole thing and try saving that without internal data storage
- convert the whole thing or very important parts into a meta node and share that
- take screenshots so at least you would know the structure of what you did
This is not very elegant but might preserve some of your work.