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I have a large collection of files (87.3 GB and 80054 objects) which I am copying from drive to drive. To make sure everything went well, I have made a checksum file to check with md5sum -c checksums.txt. Every time I try this, suddenly lightdm crashes (at least that's what I think is happening), and I am presented with the login screen. My session is gone.

What might cause this?

Does md5sum has a limit to how large checksum files or number of files it can handle? (Limited by system specs?)

Info: checksums.txt is 7.6 MB and has 79281 lines. The destination drive is an external NTFS formatted one. I run Ubuntu 12.04

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Update: I managed to successfully check all files by dividing the original checksum file into a few smaller ones. – beruic Jan 30 '13 at 9:00

md5sum doesn't has limitation of checksum files or number of files, but maybe the problem is that md5sum can not handle subfolders. Try to install md5deep, which allow to make checksum for subfolders recursively and works smoothly with large number of files.

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Doesn't seem to be the problem, as it works when I split up the original checksum file. – beruic Jan 30 '13 at 9:01

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