"File was not found" while saving alredy existing files

file

#1

I have several files, while trying to save changes, whether as the same file or by “save as” with a new filename, it shows a message saying the file does not exist.
In addition, each time I try to save, it creates a .skb file, such as “1.skb”, “2.skb” that contains the changes I’m trying to save