Make sure you're using the most recent version of Illustrator. Choose Help > Updates, or update Illustrator via the Creative Cloud desktop app.
Find out what to do if pasting artwork becomes slow or if you find unexpected data in your Illustrator files.
When you paste artwork within or between Illustrator files, the action is much slower than expected, or there are unexpected global objects in the target document (e.g., swatches, symbols, and brushes).
Try one or more of the following solutions, depending on which version of Illustrator you're using.
Choose your version of Illustrator:
Download the following ZIP file, and extract the contained script (JSX file).
Launch Illustrator and run the script: Choose File Menu > Scripts > Other Scripts or drag the script into Illustrator. The following message appears: "fixBadPluginGlobalObjectNames preference has been turned ON".
Rerun the script, if this message appears: "fixBadPluginGlobalObjectNames preference has been turned OFF".
Quit and relaunch Illustrator, and then open the affected Illustrator file to verify that it's fixed.
Solving the issue for Illustrator CS5 and earlier requires one of the two following solutions. If the first solution doesn't fix it, try the second one.
Find the Adobe Illustrator preference file. For example, preference files for Illustrator CS5 are located here:
On Windows, the Application and AppData files are hidden by default. If you need help revealing hidden files, see Show hidden files.
Open the preference file in a plain-text editor such as TextWrangler (Mac OS) or Notepad (Windows). (You can also use a more traditional word processing app. If you do, save the file as plain text without allowing a hidden .txt extension.)
In the preference file, find the section that looks similar to this:
Change the enableContentRecovery value from 0 to 1. If the /aiFileFormat section doesn't have an enableContentRecovery line, add one. After your edit, it should look like this:
Save the preference file without allowing a name or extension change.
To open the document, choose File > Open or press Command+O.
Do not open the document by double-clicking it, using the Recent Files list, or dragging the file onto the Illustrator app icon.
In the file navigation dialog box, select the file that you want to repair.
Press Command+Option+Shift (Mac OS) or Ctrl+Alt+Shift (Windows), then click Open in the Open dialog box.
Close the blank window without saving it.
In Finder (Mac OS) or Windows Explorer (Windows), in the same directory that contained the original file, find a copy of the file preceded with an underscore. For example, if you opened "BrokenFile.ai," you see a new file named "_BrokenFile.ai."
Open the underscored file in a plain text editor such as TextWrangler (Mac OS) or UltraEdit (Windows). (Windows users should be able to use WordPad or Notepad as well). If the broken file is large, it can take a while to open. If your text editor has a maximum limit on the size of files it can open, use a different text editor.
In the underscored file, search for every instance of this:
Check the following line to see if it matches one of these strings:
(Adobe Calligraphic Brush Tool)
(Adobe Scatter Brush Tool)
(Adobe ArtOnPath Brush Tool)
(Adobe Pattern Brush Tool)
If the line doesn't match one of the four strings exactly (including case), then select all of the text within the %AI8_BeginPluginObject comment and the first subsequent %AI8_EndPluginObject comment. Then delete the comments themselves, and delete the selection.
Repeat steps 9 and 10 for every instance of the %AI8_BeginPluginObject comment in the file.
Delete all the symbols and then all the brushes. Or, if you suspect the file contains necessary symbols or brush strokes, run the Delete Unused Panel Items action (choose Actions > Delete Unused Panel Items, then click Play Current Selection).
Save the file with a new name (e.g., "Fixed File.ai").
(Important) Close the file.
Reopen the file in Illustrator. Verify that the file is fixed by selecting any object and copying and pasting it into a new blank file.
Unexpected content is caused by issues from past versions of Illustrator that have been fixed in the current version. If you're working with a document saved in a previous version of Illustrator, opening the file in the current version may not fix the issue.
Unexpected global objects can appear in their respective panels, or not. Attempts to delete the unexpected global objects could fail, or could cause Illustrator to become unstable and quit suddenly.
If you save the document, then the document size shows a marked increase due to the amount of global objects added to the document. This invalid data can exist in a document long before it's noticed, so opening the document in previous versions doesn't always fix the issue. The invalid data can spread when you copy artwork from one document to another.