Same issue starting today. I did find a somewhat helpful workaround on the Adobe Support Community where it is mentioned to save the document as an SVG, open the SVG and then save it to AI again.
Worked for me. Only downside is that if you work with multiple layers you'll now have one layer with the previously created layers as groups inside. You'll have to release these back to layers and rename all layers again. Works, but time-consuming...
Hope it helps. Here's also the link to the community entry:
Same issue starting today. I did find a somewhat helpful workaround on the Adobe Support Community where it is mentioned to save the document as an SVG, open the SVG and then save it to AI again.
Worked for me. Only downside is that if you work with multiple layers you'll now have one layer with the previously created layers as groups inside. You'll have to release these back to layers and rename all layers again. Works, but time-consuming...
Hope it helps. Here's also the link to the community entry:
https://community.adobe.com/t5/illustrator/can-t-save-file-this-file-cannot-be-found-error/m-p/11808494