Nodered 14.4 update apparently breaks write to file

Yesterday, nodered did an auto update to 14.4 and it completely broke my access to flows. I couldn’t get back into the nodered workspace.

After a bit of messing about searching for solutions on the net, I managed to get nodered working again but only after completely doing a fresh install, messing about with backups which would break it again, etc (I have definitely learnt the value of backing up each flow as a separate downloaded file).

Having recovered all my flows, I noticed that one flow which heavily relies on sending info to and from a file for manipulation wasn’t doing so. On further investigation, I noticed that the following section …

contextStorage: {
   default: "memoryOnly",
   memoryOnly: { module: 'memory' },
   file: { module: 'localfilesystem' }
},

was not longer in the nodered setting file - so I reintroduced it and I instantly could no longer access nodered. Went back and removed it from the settings file and I could immediately access nodered again. No other changes in between.

So the questions are;
1 - is this a bug that breaks nodered,
2 - am I doing something wrong/out-of-date wrt setting up local file access
3 - how can I revert to the last 4.3 version of nodered?

Any advise/help/pointing in the right direction would be most welcome, and thank you to all those who give their time to help numpties like me …

Nodered 18 is bugged,downgrade nodered17