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Re: "MCID" errors in PDFs

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From: Dave Comeau
Date: Apr 18, 2023 7:18AM

Hi Karen,

Duplicate MCID errors tend to occur when multiple tagged PDFs have been combined in a way that doesn't re-assign tag IDs when both documents use the same ID values.

This gets discussed a lot in the PDF Accessibility Facebook group.

Suggestions often include extracting (removing) individual pages and then rechecking the document to locate the offending page(s). Then delete and rebuild the offending tags in the original document.

Reportedly, AxesPDF can usually fix these errors using its Quick Fix tools as well.

Using Acrobat Pro's preflight tools can sometimes also work. Go to Print Production > Preflight > Select Acrobat Pro DC 2015 Profiles from the middle dropdown. Click the blue wrench icon to search and select "Insert missing Type entry in StructElem objects" or "Fix problems in PDF tagging structure".

Hope that helps,

Dave


From: WebAIM-Forum < <EMAIL REMOVED> > on behalf of Karen McCall < <EMAIL REMOVED> >
Sent: Monday, April 17, 2023 1:25 PM
To: <EMAIL REMOVED> < <EMAIL REMOVED> >
Cc: ATHEN < <EMAIL REMOVED> >
Subject: [EXTERNAL] - [WebAIM] "MCID" errors in PDFs

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Afternoon Everyone!
I'm trying to find information on an error that seems to be cropping up more and more. It is that a PDF has a "missing MCID" or a "duplicate MCID".
If you've encountered this error, can you tell me:

1. What accessibility checker you were using.
2. What was the "authoring" tool that created the PDF?
3. Does it show up on untagged PDF that is then tagged?
4. Are the PDFs that it shows up in single PDFs or a PDF created by combining PdFs?
Any help you can provide to assist in tracking down this error message will help find a solution.
If you have a solution, let me know. From what I've read the only solution is to retag the document.
If you have any samples that can be shared, that would be helpful too. So far, I haven't been able to see this error.
Cheers, Karen