CryFS 0.10 or later is stable for most use cases, but has a couple of known issues that can corrupt your file system. They don't happen in normal day to day use, but can happen if you don't pay attention or aren't aware of them. This is why the version number hasn't reached 1.0 yet.
If you kill the CryFS process while it was in the middle of writing data (either intentionally or unintentionally by losing power to your PC), your file system could get corrupted. CryFS does not do journaling. Note that in 0.10.x, read accesses into a CryFS file system can cause writes because file timestamps get updated. So if you're unlucky, your file system could get corrupted if you lose power while you were reading files as well. Read accesses aren't an issue in CryFS 0.11.x anymore, because it mounts the filesystem with noatime by default.
The same corruption mentioned above can happen when CryFS is trying to write data but your disk ran out of space, causing the write to fail. хм.. яснопонятно, не стал бы рисковать
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