Is it dangerous to add/remove a hard-drive to a Windows machine which is in stand by?

Question

Can I add a SATA drive to a Windows 7 machine which is in standby mode? The hardware supports hot-plug.

Could pulling the drive out while in standby corrupt the data on the drive (unflushed caches, ...)? Does Windows flush before standing by?

How about swapping a drive with another drive of different kind (SSD -> mechanical disk) and size, also while in stand-by. Could the OS when waking up believe that the old drive is still there, and write to it and thus corrupt it, since the new one has different partitions and data?

Answer 1

Your drives need to be set to AHCI, this enables the hot swapping features of SATA drives.

Now, all your SATA drives will appear when you use the “Safely remove device” icon near the clock in the bottom right corner. If you choose to remove a drive, you can eject it from there and then take it out and put in a new one. This is where the problems start to arrive though. Sometimes, this approach works without a problem, but sometimes Windows simply goes silent, and acts as though nothing has been connected at all. Other times, it tells you that it has found partitions, but that they are in RAW format, and have to be reformatted!

After living with this for a couple of days, I decided that there had to be a more stable way of doing this, and that was when I came across HotSwap!. This piece of software is made for managing hot-swap drives in Windows, and once installed, allows you not only to scan for new drives ( and load them properly! ), but also to safely remove them AFTER doing a spin-down.

After running this stand-alone .exe, you can set it to autostart with Windows. After that, whenever you want to swap a drive, just right-click the hotswap icon at the bottom right near your clock, safely remove the device you want to swap, exchange the drives and choose “Scan for changes” in the HotSwap! menu and up comes your drive!

Happy hot-swapping!

Text taken from here

Answer 2

Yes, data is flushed when going into standby, but considering it may not be 100% foolproof. I always assign different drive letters to all my usb devices, this can prevent some issues when doing what you suggest.

http://gsmblog.com/post/Difference-between-S1-(POS)-and-S3-(STR)-standby-mode-in-BIOS.aspx

S3 (STR) Standby: In this state, the CPU has no power, the power supply is in a reduced power mode, main memory (RAM) is still powered, although it is almost the only component that is. Since the state of the operating system and all applications, open documents, etc. lies all in main memory, the user can resume work exactly where they left off the main memory content when the computer comes back from S3 is the same as when it was put into S3. S3 has two advantages over S4; the computer is faster to resume than to reboot, secondly if any running applications (opened documents, etc) have private information in them, this will not be written to the disk. However, disk caches may be flushed to prevent data corruption in case the system doesn't wake up e.g. due to power failure. STR means Save To RAM. In modern operating systems it's called as: Standby in versions of Windows through Windows XP and in some varieties of Linux, Sleep in Windows Vista and Mac OS X.