"the file _____.ai is an unknown format and cannot be opened"

[saraht774]

Okay! So I've been running into this problem all the time and I think I know what caused the issue but I don't know how to fix it. 

I have a creative cloud subscription and only started saving documents onto the cloud right about a year ago. I haven't really been needing to go back into my older files much but when I do, I can't open them. 

I think what happened was when I downloaded Adobe Illustrator 2021, I deleted the Adobe Illustrator 2020 application, and I think illustrator is angry with me because the older files aren't from the 2021 version. I don't know why this is happening nor how to fix it. I really would appreciate any help as I don't want to lose everything I've done up until April 2020! 

[Ton Frederiks]

You are not using Adobe cloud services, but Apples iCloud Drive.

What happens if you first download them to your internal harddisk?

[Michael J. Hoffman]

I agree with Ton. Take a close look at the info panel you presented:

A 62Mb file but only taking 4k on disk - either as Ton says, not downloaded from iCloud, or very corrupt (I'm going to guess not downloaded, since you have multiple of these).

[saraht774]

Unfortunately, many of them are downloaded, and this file is also downloaded.