Select File > Save As.
Last updated on
Oct 20, 2026
Learn how to resolve the "An unknown error is detected" message in Adobe Illustrator when saving files in .ai format.
When you save a file in Adobe Illustrator, the message "An unknown error is detected" may appear and prevent the file from being saved in .ai format.
Find the causes and follow their solutions in sequence.
AI file format compatibility issue
Save the file as a PDF and then save it again in .ai format.
Select PDF as the file format and save the file.
Reopen the PDF in Illustrator.
Select File > Save As, and then select Adobe Illustrator (*.AI).
If the file saves successfully, no further troubleshooting is required.
Corrupted fonts or text objects
Select > Object > Text Objects.
Select Type > Create Outlines.
Save the file.
If you need to keep the text editable, replace any suspected fonts with a different font before saving.
For guidance on converting text to outlines, use Reshape text using outlines.
File handling preferences conflict
Disable file handling preferences that can interfere with save operations.
Open:
Windows: Edit > Preferences > File Handling & Clipboard
macOS: Illustrator > Preferences > File Handling & Clipboard
Disable Optimize File Open and Save Time on Slow Networks (Beta), if available.
Disable Save in the Background.
Select OK and then save the file.
Default PDF preset issue
Reset the PDF settings folder.
Navigate to the PDF settings folder:
Windows: AppData\Roaming\Adobe\Adobe PDF\Settings
macOS: ~/Library/Application Support/Adobe/Adobe PDF/Settings
Rename Settings to Settings old.
Create a new folder named Settings in the same location
Create a new folder named Settings in the same location
Relaunch Illustrator and then try saving the file.
Custom PDF preset issue
Select Edit > Adobe PDF Presets.
Identify custom presets that use PDF compatibility version 1.3.
Quit Illustrator.
Navigate to the PDF settings folder:
Windows: AppData\Roaming\Adobe\Adobe PDF\Settings
macOS:~/Library/Application Support/Adobe/Adobe PDF/Settings
Remove the PDF 1.3 preset files.
Relaunch Illustrator and then try saving the file.
If none of these solutions resolve the error, Adobe recommends sharing your presets folder and the problematic file in a zip format with Adobe Support for investigation. Contact Adobe Technical Support for additional assistance.
Resolve additional save failures, including damaged files and Error 5000, in Fix Illustrator file save issues.
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