Can you tell us the error?
I'm sorry, my english is not good enough. I send ss of pop up message when I trie to open document.
Did something unexpected happen while saving the file? Were you saving to a network?
This indicates the file has been damaged somehow. Do you have a backup you can use?
Unfortunately, I don't have backup documents, which is my problem.
The only thing that is more or less usable are the PDF files that I sent by email.
These documents can be opened in Illustrator, but unfortunately all fonts have been converted to curves, so they are relatively unusable if the need for interventions in the text.
I don't see a way to recover these documents.
I don't know what happend. There are no linked elements in the document, the document is not too heavy (only about 2-3 MB). I saved it as I usually save other documents, after saving I converted them into PDF documents and saved them as PDF. The directory contains both documents (Ai and PDF as on ss), shows their size, but I can't open them.