Is It Safe to Remove USB Drives When a Computer Is Asleep?

We have all heard the admonition about safely removing USB devices when we are done with them, but what if an operating system is suspended and you decide to simply unplug the USB device then and there anyway?

The Question:

We are often cautioned against unplugging USB drives in case they are currently being read from or written to. When a computer is suspended, hibernated, or asleep, it is obviously not writing any data. It may have been in the middle of a read or write operation, however, and it will have put such an operation on hold.

Since no arms are moving (for USB hard drives), or bytes on the drive flickering on and off (for flash drives), is it then “safe” to unplug the drive in question?

Is this true even if data was being written to it, but the operation was temporarily suspended? (Assuming you do not mind that specific file having been only half-written to the USB drive.)


Is it safe to remove USB media when a computer is suspended?


The Answer


While there are indeed no transfers going on, the reason you do the Safely Remove Hardware dance is not because of the transfers. You are doing this to cleanly unmount the file system. Programs may still be using the USB drive and some files may still be unwritten to the disk, even after the application using them is closed. This is the same reason why you do not just hibernate and switch operating systems. A mounted file system is never guaranteed to be in a consistent state.

Ever wondered why an operating system slowed down to a crawl when using floppies? It is because the cache was flushed after writing each sector so that the floppy could be removed at any time when not in use.

You will still get a dialog pop-up and your program will hang if you try to access a floppy that was removed behind your back. Just insert the floppy back and be done. This will not work with USB drives because they get a different identifier each time. The program will just crash and the operating system may too if a driver was accessing a file.

Sometimes, its just funny you see guys copy some to a drive, when done.... they ask windows to check whether the drive is still in use ...... the newbies will do the "safely remove hardware dance" till they land on a topic like this ......Unless data transfer or a document is open on the drive... you can actually remove the drive any time you wont but you must be sure because it may render data corrupted if they are in use.

I once remember i was actually copying files onto my pendrive.. using a desktop PC ... then my lights went off... as usual in GH... wen it came back on the pendrive was totally damaged... I was shocked... but then I figure it put that the problem was with the SUperCopier app. i was using... Honestly I have neva used the application ever again since 2010...