Very long lag after clicking Error Checking > Check Now > "Start"

HP EliteDesk 800 G1 PC. Running fine for over a year, very carefully maintained. SSD for OS/apps and HDD for data. Recently added another drive, an SSD, for video editing data and seem to work fine. Optimized SSD drives with Samsung Magician and guidance from Storage Editor at Overclock.net who specialized in SSDs.

Today got blue screen while the machine was idle, of the type that caused the machine to reboot on its own. I told it to start Windows normally. It went into Windows, and gave me a message saying it didn't shut down properly (it did NOT say "System recovered from a serious error).

All seems fine. I ran CHKDSK on the C: drive (Error Checking from in Windows, with the first box for "Automatically fix file system erros" left checked on, as it is by default). It found no errors. I ran "sfc /scannow" and it found no errors.

HOWEVER, on running Error Checking, when I went to initiate it by hitting Start, it showed me no response at all for about 30 seconds, before finally giving me the message saying it has to do a restart to run the check.

On multiple tests, doing a reboot before each test, this lag has persisted and yet it's also been intermittent. On about fifteen tests, it happened about ten of those times. It was happening each time non-stop until I disconnected the external USB3 card reader and the newly connected SSD, at which point, on hitting Start, the message saying it needed to restart came up instantly -- on two tests in a row. But then I put the two devices back and it still was instant two times in a row, and then reverted back to a lag -- of 20 seconds one time and a full 60 seconds another time.

I've used Windows 7 a long time and I've never seen anything like this on a properly working system.

This is a highly mission-critical system with a lot of people relying on the company's successful operations.

I can restore the OS/apps from an image backup that's less than a week old (and keep my current data since it's on the other disks), but it was sent out of state and it will take a few days to get my hand on it.

I know this is a long post but I'm in the midst of grueling responsibilities and work load, and it's a very tough choice whether to use a different machine until the backup drive is in my hands, or to keep working with this machine and ignore both the blue screen and this peculiar lag on hitting that Start button. (I'm ignoring the blue-screen event anyway since I'm writing it off as a fluke, which we all know can happen on perfectly solid machines once in a blue moon, or in ten blue moons. If it happens again I'm replacing the machine, unless the cause becomes incredibly obvious -- I didn't try to read the screen when it happened.)

My question is whether this long lag on hitting Start to run a disk check suggests possible OS corruption.

Thanks so much!

Hello rocketman6 after your blue screen please follow this tutorial...

Blue Screen of Death (BSOD) Posting Instructions

I appreciate the advice, and may yet go start a thread in the BSOD forum and provide the DM log etc.

But right now I'm doing my version of troubleshooting and decision-making as a pretty experienced computer user and someone with a lot of responsibilities on my plate. I ask that you please respect my judgment and allow me to make decisions on my risks and time commitments and that you help me with the question I've presented the way I've presented it.

The question again is whether it is common, uncommon, or even unheard of for that Start button to take as much as 30 to 60 seconds to produce the subsequent message and prompt on a properly functioning system.

(My judgment is that if it's normal or reasonably common, then I will probably assume, based on all my on-site observations and my experience and better judgment, that this BSOD was a fluke and I can ignore it and go back to work -- and assume the OS is entirely unscathed. If it's not at all common or is unheard of, I need to restore the system from backup and not rely on it until that's done. And, entirely separately, I research the BSOD issue to see if I can determine the cause -- or first wait to see if it ever happens again. Whatever I decide, I can more readily make a well-informed decision if this current question is answered.)

THANK YOU!!!