Illustrator says file is not compatible or is an unknown format when installing brushes, swatches or graphic styles.

If you're attempting to install your Adobe Illustrator brushes, swatches or graphic styles and you receive an error that says the "file is not compatible or is an unknown format", it is usually because the file has been damaged during download or unzipping. 

To fix this error try the following: 

1. Check the product page or documentation to confirm you have the correct version of Illustrator.

2. Delete the downloaded product from your computer.

3. Restart your computer.

4. Download your files again and re-install. 

If you continue to have difficulties please submit a support request below.