File not found error when opening an ai file.

[#1]

When I recently switched computers to work at home, I put all my files in Adobe Creative Cloud.  When working at home I download the file and open... However some files show as do you want to replace as it cannot be found.  

Why is this happening on all my files?

[#2]

When I recently switched computers to work at home, I put all my files in Adobe Creative Cloud.  When working at home I download the file and open... However some files show as do you want to replace as it cannot be found.  

Why is this happening on all my files?

[#3 · Accepted solution]

When you placed your images into this project, you likely created a link to the original location of those files. So, even though you moved your Illustrator document, you either didn't also move the associated files, or changed their relative location to the original. To fix this, either embed your placed files, or create a package. This creates a new folder with all your linked files, and changes Illustrator's information on their relative position in the file system. To learn about packaging, see this article:
https://helpx.adobe.com/illustrator/using/package-files.html

[#4]

Thank you for the further information.  I will need to change the way I save files moving forward. TY