Issues with Cryptomator for DVD / Blu-Ray Data Backup

Hello everyone,

I use Win10 Pro and Cryptomator and I really like it. I’m a beginner with backups and Cryptomator. I would like to encrypt backups not only when saving them on hard-drives (which works fine), but also using optical media (single write) like DVDs or Blu-Rays for long-term data backups. I don’t need to mount them or similar, it’s okay to just check them every year if they checksums are still fine.

I experimented a lot with several attempts and I still have issue, maybe you could help me?

That’s what I did:
a) I have just regular files to backup, like documents, PDFs, images, videos. But nothing special, no file size bigger than 4 Gigabytes (most of them just a few MB up to 100 MB) or crazy deep file paths or file names.
b) I created a new vault on my hard drive, copied all the backup data in it, created checksum files for them, put them in too and then closed the vault.
c) Then I start CD Burner XP, choose UTF as a format and burned all the crypted data on a 8,5GB DVD.
d) For testing I put the finalized DVD in another computer, copied the whole vault data (still encrypted) from this DVD on the computer’s hard drive and then opened the vault from the hard-drive. When I then re-read the checksum files, they show me that about 1-3 % of the data files can’t be read because they are not there anymore, so they are missing.
e) I generally use Teracopy (which also checksums all files when copying from one folder to the other) and I also let CD Burner XP check the DVD after burning if all files are there, which is positive. But once I try to copy the files from the then re-opened vault after copying it on the hard-drive, Teracopy already makes alarm that some files are missing.

Do you have any idea where the 1-3 % of the files are going?

Thanks, E

Hi. Although I’m convinced that Cryptomator was not designed for data backups on DVD, it should theoretically possible (I personally would use other software for this).
After all, you do nothing but burn files to DVD. If you miss files on the DVD, I would assume the issue during the burn process.
To investigate in this, I recommend the following:

  1. is there a log file of the burn process?
  2. which files exactly are missing? You can try to find out e.g. with winmerge.
  3. is something exceptional with the missing files?(long names, big size, etc)

From my point of view this is not a Cryptomator issue, but a burning issue.

Thanks Michael for your answer.

Some new findings:

a) I tried again and this time I selected about 1.500 files forming 500MB and I burned them in the normal not encrypted version on the DVD and within the same burn process also the encrypted version. So I can compare. After burning, I copied the whole DVD data to my HDD again and checked the checksums. The not encrypted ones were perfectly fine 100% all files there. The encrypted ones were missing about 10% its files. And both on the same single DVD. Important: I made checksums before and after encryption and through burning both the encrypted and also later the then de-crypted files were missing about 10%.

b) I think I found a solution: After encrypting when I zip the closed Vault with 7zip in a *.tar File or similar, I have no problems anymore. So my understanding is, that this would be the proof that something makes the burn process incompatible with the long filenames within a vault? Because when the filenames are hidden within a TAR Archive (or ZIP Archive), then there’s no problem?

c) Although I copied the whole DVD encrypted data to my hard drive and I tried to open the vault from there, it only worked when I have chosen “Read only” in the Cryptomator settings.

Looking forward to other people trying to use Cryptomator with DVDs / Blu-Rays for Backups!

Cheers, E