Program Error opening file

I have been recieving this error when attempting to open some files:

Could not open "XXX.psd" because of a program error.

A workaround is to open the file with Gimp - which is free software - and re-save as a psd file. Gimp retains the layers, but does, however, dispense with other stuff such as Colour Fill layers and vector shapes. A better alternative is <LINK REMOVED>(there are probably similar sites) which allows you to re-save the file losing nothing.

Such files can then be opened again in Photoshop with no error.

Strangely, if the file is thereafter edited in Photoshop in any way - even to simply hide then show a layer - and saved from within Photoshop and closed: any attempt to re-open the file with Photoshop will invoke the familiar error... It seems to me there is something about how Photoshop handles layers when saving that makes them impossible to re-open with Photoshop; saving a formerly dodgy psd as a tif within Photoshop creates a similar error when trying to re-open it: "There was a problem reading the layer data. Read the composite data instead?" If you choose the "Read.." option, you get a flattened version of your file... So probably Photoshop is handling layers badly on save/open. That other software can open these files should embarrass Adobe.

I've tried different prefs and troubleshooting - such as saving without thumbnail, generator, GPU - etc etc. nothing works so far. I would be interested to know if anyone else is receiving this error trying to open a previously okay file and if there is a pattern.

v 24.5.0 Apple M1 Ultra 128gb RAM OS 13.3.1(a)