Hi there,
Sorry about the trouble. It seems the file is corrupted. Could you please share a few more details like:
- OS and version of Illustrator
- What was the last action you performed which led to this error?
- Is the issue related to a specific document?
- Could you please share this document with us? You can upload it to the Creative Cloud (https://helpx.adobe.com/in/creative-cloud/help/share.html) and share the download link here.
We can try to recover it. I must also inform you that file recovery can't be guaranteed with 100% success. We'll surely try our best.
- Where are you saving the files (Network Drive/ System HDD/ Shared Folder on System/ External HDD)?
- Are there any recent changes made to your system? For example, any antivirus, system updates, plugins, or web extensions installed recently.
- Does renaming the .Ai to .pdf help resolve the issue. Does it open in Adobe Acrobat?
We are here to help. We just need more information.
Thanks & Regards,
Anshul Saini