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AI CS6 | Mac | The file "" is in an unknown format and cannot be opened.

Mar 26, 2013 3:47 PM

Tags: #illustrator #adobe #mac #cs6 #trouble_shooting #open_file

I just did a wholesale back-up by copying my entire folder of working files onto an external hard drive. After doing so, I noticed that each AI file on the original drive no longer displays previews, and when I attempt to open them I get the warning "The file '' is in an unknown format and cannot be opened." The problem files were created in CS6 and saved with the following settings:


Subset fonts when percent of characters used is less than: 100%


Create PDF Compatible File

Use Compression


(Coincidentally, I'm having the same problem with  PDFs. That error message is, "Acrobat could not open 'XXX.pdf'' because it is either not a supported file type or because the file has been damaged [for example, it was sent as an email attachment and wasn't correctly decoded]." The issue with the PDFs is not as critical as the AI files, so I'm focused on trying to solve the AI problem for now.)


I'm not sure that the back-up caused the problem, but the problem occured right afterwards.


I've tried the following:

• placing the file within another AI doc

• contol click to open via the Finder

• opening with Acrobat

• opening with Photoshop

• placing within InDesign

• changing sharing and permissions in Get Info

• cooying and renaming the file


Any recommendations would be really appreciated.


Thank you.

  • Currently Being Moderated
    Mar 26, 2013 4:21 PM   in reply to kooloodee

    Do the backup copies of your files work? I think I wouldn't try them on your computer, but somewhere else.


    Actually this looks like the copying caused the trouble. Did you use a tool for it? Or just drag and drop?

    Did the file size change as well?


    If dragged and dropped: did you check the integrity of the hard drive lately? When a simple read-operation can ruin files, this is very scary and looks like some serious error. How old is the drive? Do other files still work? Have you ever had problems with the drive?


    Although you already checked most of what in here, you might want to read it: -files.html

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  • Currently Being Moderated
    Mar 26, 2013 5:17 PM   in reply to kooloodee

    If a drag and drop operation causes this kind of trouble, I would check the integrity of the drive ASAP. There is this Apple disk utility which can do that or you use third party tools.

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