Disk is full error Message importing back to LR from PS

I edit in both LR and PS. Newest versions of both...both recently updated.

Here lately, I get this error message when trying to import back INTO LR.

"Could not save as F:/......psd because the disk is full"

HUH?

Sometimes when i reboot my computer it works fine, but lately, not even that is helping.

Thanks so much!