Flash disk is just unsafe.
I’ve used 4-5 flash disks. Some ended up broken, losing all the data on them. Some have been upgraded or lost. And I’ve found file damage is quite usual on them. Sometimes an old word document, which has not been opened for a long time, is suddently being reported damaged. MS Office files still have chances to be recovered, other formats will not be so lucky. Sometimes, it just changed some .txt files to 4K empty files.
It’s weird. And I’m already transfering my important tech notes to Google Docs. Though a little bit slow due to network connection, at least I don’t have to worry about the storage media any more. And I’ve got a more awesome search capability.