1. A colleague had given me a large 33Gb .mov for use in a project, I put this file on a backup drive.
  2. I made an identical copy of this 33Gb .mov file and placed it in a folder that I'd use to work on a Premiere Pro Project.
  3. I ran Adobe Premiere Pro CS6 and dragged in the 33Gb .mov file into the Sequence (imported it)
  4. Premiere Pro CS6 started conforming the file.
  5. After it had finished, I noticed that it's Modified Date was just now i.e different to the Modified Date on the original copy of the file on the backup drive (see step 1)
  6. I ran a BeyondCompare check between the .mov file on the backup drive (see step 1) and the one that the Premiere Pro project was using (step 2, 3) and Beyond Compare reported they were different.

I had initially thought it was unrelated file corruption of some kind, but I have checked this several times and got the same outcome, so it's definitely Premiere Pro deliberately modifying the file.

So I am puzzled: these are supposed to be the same file.

Why would there be a need for Adobe Premiere Pro to modify the footage? What does it do to the file? Would it not be better to create a separate file if necessary?

I can accept this if that's how it works and it's good to know that it was Premiere Pro deliberately modifying the files and not corruption (so my hardware ought to be healthy). But it makes more sense to me if Premiere Pro made separate modified copies for its own use. Modifying the file as it does hinders my process for checking the integrity of backups; if the original asset footage files were the same as earlier copies then it would be easy to know that the backups are OK.


1 Answer 1


It's all about this setting, "Write XMP ID To Files On Import" - which confirms that Adobe Premiere Pro is deliberately modifying the .mov file: http://helpx.adobe.com/premiere-pro/using/preferences.html#WSE3BD4A43-7022-4fe6-97F5-95313935347B

These posts give some background as to why having this setting enabled would be beneficial: one benefit being to be able to skip conforming files by matching the conformed file with the original using the embedded XMP tag :-

(Found using Google search term "adobe premiere pro date modified")

(will accept this answer, when 2 days has elapsed)

  • 1
    Cool, glad you found it. I was going to suggest the same that it is meta data changes, but glad you found the specific meta data change. The conforming does write out to separate files stored in the scratch disk, so source files should never be meaningfully modified beyond some meta-tagging. It's basically just adding a serial number to the file for better identification. This can be very key if you start using multiple prints of a scene in your production pipeline, though your personal pipeline may be simple enough it doesn't matter.
    – AJ Henderson
    Commented Dec 24, 2014 at 19:35
  • +1 Thanks @AJHendersonfor the support, particularly the point about multiple prints. Commented Dec 29, 2014 at 7:54

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