Comments on: Examination Failed(Cannot unmount disk) Error https://qnapsupport.net Advanced Qnap Technical Support Sat, 11 May 2019 19:51:17 +0000 hourly 1 https://wordpress.org/?v=3.8.31 By: Pedro Pombeiro https://qnapsupport.net/examination-failedcannot-unmount-disk-error/#comment-44820 Mon, 14 Nov 2016 14:56:08 +0000 http://qnapsupport.net/?page_id=10108#comment-44820 In my case, I had to pass the -l flag to umount, otherwise it wouldn’t let me unmount
/dev/mapper/cachedev1. From the documentation:


There are several options that can be tried in the event that umount refuses to unmount a filesystem for no immediately apparent reason. Perhaps the most useful is the -l (i.e., lazy) option, which immediately detaches the filesystem from the main filesystem and then cleans up all references to the unmounted filesystem as soon as it is no longer busy. This capability requires Linux kernel 2.4.11 or later.

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