I requested a copy of all of my Facebook data, in HTML format. It gave me five zip files ranging from 2.8GB to 4.7GB to download, totaling 19GB. Those archives contain sub-folders named messages, posts etc.

I made the assumption that they should be merged since there was only one index.html as an entry point and there were folders with the same name (like messages for example, which was present in all of the archives).When I tried to extract all of them, I noticed that the extractor (Winzip) told me that there were duplicate files and asked how I wanted to handle them (keep the old copy or replace). From the few files I checked, the size was exactly the same so it probably was exactly the same file.

I couldn't find any pattern on the files I checked (after the prompt), and at this point manually reviewing to search for missing data is pointless (I can't exactly remember what I posted or what messages I sent years ago).

When the extraction was completed, the unzipped files were around 90% the size of the archives, so I am assuming that the amount of duplicates was quite large.

Why would this happen? Some of my hypotheses are that this has to do with facebook trying to split the data into five zip file for easier download or because their database is convoluted, or that my data is simply corrupted somehow.

Is there a way to be sure that this is normal behavior and my data is downloaded correctly?

  • Welcome to Web Applications! Please take the Tour and review How to Ask. Then edit your post to be a practical question about using a web app. What data were you expecting? What did you select for download? What was the size of each Zip file? Was something missing? What files were duplicated? Why do you think some of your data was corrupted? Note that questions about whether or not Facebook's DB is convoluted or "why" they make certain design decisions are off topic.
    – Blindspots
    Aug 27, 2023 at 19:58
  • The question lacks any detail about each archive's structure/contents, the reason why you merged them, & what exactly was overwritten. I suggest taking a step back to do additional research on your end. eg. Extract each archive to its own folder. Are they self-contained? Is there more than one with an index.html file in the top folder? Comparing the archive contents/folder structure (DIF) may help you as well. It's unclear the method you used to extract & merge the files but FB could easily build their archives to trigger it automatically if it was the intended behavior.
    – Blindspots
    Aug 28, 2023 at 16:12
  • If this was a question about ZIP tools or DIF tools then Super User might be the appropriate site but be sure to review their site FAQ before posting.
    – Blindspots
    Aug 28, 2023 at 16:36
  • I’m voting to close this question since it hinges on the unsupported assumption that the archives are intended to be merged. It also isn't clear if the files are actual duplicates nor their properties & source. Feel free to edit the question to be considered for reopening after reviewing the feedback in this comment as well as the ones above.
    – Blindspots
    Aug 28, 2023 at 17:15
  • Comments have been moved to chat; please do not continue the discussion here. Before posting a comment below this one, please review the purposes of comments. Comments that do not request clarification or suggest improvements usually belong as an answer, on Web Applications Meta, or in Web Applications Chat. Comments continuing discussion may be removed.
    – Blindspots
    Aug 29, 2023 at 0:16


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