Strange boot behaviour ('partial hangs'). Any ideas?

Over the past several weeks one of my PCs (Win7 x64) has been exhibiting rather odd behaviour at boot - and sometimes at a reboot too (though less often). I get to the desktop fast enough, but although some startup items run (like batch scripts, run from the startup folder), others do not do so for perhaps 45" or so after the desktop appears (an example is a vbs script in the same startup folder; also my All_CPU desktop gadget hangs for the same period). If I try running certain programmes, say, MS Flight Simulator, that doesn't start until this 'partial freeze' ends, even though the process is immediately visible in Task Manager (zero CPU usage for the duration). MS Office programmes (for example) will run straight away however when I click on a shortcut to them. It's all very confusing: why some and not others? And why even at a boot from cold, don't I get the issue every single time?).

My SSDs test out healthy and I ran MemTest for several cycles with no problems. I have run tests on the GPU and CPU with no obvious problems being shown.

If I open the Task manager during this period after boot, (TM also opens fine), all CPU usage is at zero.. I wait and after some time, the rest of the programmes which also used to run immediately the desktop was visible come to life and CPU % values in TM start to show... After which everything is normal for as long as the PC is running. No performance issues or whatever...

I have run a several boot traces, using ProcMon, but they are inconclusive: it is probable that any delays that show are the result of the underlying problem, rather than the cause of it. Certainly stopping those programmes from running at startup didn't stop the problem from occurring. I have also tried a couple of boot traces using xperf, but firstly interpreting the results is hard and, moreover, the issue doesn't often present itself when the PC reboots, only when it boots after having been off (and even then, not every time). How would I configure xperf not to reboot, but to trace a boot after the PC has been off for a while? Is that possible? My trace parameters are, BTW: xbootmgr -trace boot -traceflags base+latency+dispatcher -stackwalk profile+cswitch+readythread -notraceflagsinfilename -postbootdelay 10

I have also run the PC via MSConfig, with various options (no startup items, no services), but that is also confusing, as for the first several boots the problem seemed to clear, but then I got the problem one time, even with MSConfig set for basic startup only, so I am not sure what to conclude.

Given that performance is fine once the glitch, whatever it is, clears itself, I think reinstalling Windows would be overkill. I wonder if the symptoms I have described ring a bell with anyone, so that I might narrow down the possibilities? (I could of course at some stage post the xperf boot results?).

Many thanks for any help with this!

not to mention reinstalling windows has every chance of reproducing the issue, lol

I'm totally guessing here but what comes to mind is that windows is struggling with hardware detection and/or initialization. Unplug and replug-in all data connectors (not power) to refresh the contact points. A bad motherboard battery would be more likely to cause an issue on a cold boot than warm boot, so you might start by replacing the battery, then reflashing the bios, even if you are on the current bios version. If that does not help, then try booting with minimal devices - just one ssd drive, just onboard video, no usb devices (if you happen to have a ps2 mouse and keyboard laying around), no network. If that does not help, really the first thing your symptoms sounded like is a failing hard drive, but given that you have an evo 850, a bad hard drive is not likely. Still could be a bad cable or connection though. And if you do have another hard drive laying around somewhere, you might macrium clone your existing ssd onto that old drive, then boot from the old drive. All of the above grows out of a guess that this is a hardware problem, hence the trial and error steps. The fact that everything is good once you're fully booted is indicative of good hardware, but that does not necessarily mean perfect connections.

Thanks... I can try those suggestions, but before I unplug everything, haul the PC out from under the desk and start unscrewing it I'd like to explore software options a bit further. It seems odd to me that, if there were some hardware problem, such as a loose connection, some programmes run at startup and not others. Surely a hardware error would not selectively allow batch scripts to run but not vbs scripts, for instance? Certain programmes seem to be wating for something. A bit odd that TM shows zero CPU usage for all processes for the duration - but it could of course simply be that although the TM interface opens, it is not actually registering anything until the mini freeze-up clears.

I wondered if some process set to run at startup is causing the issue (even though the MSConfig startup - which I will try again - gave inconclusive results). I tried Autorun and and unchecked the startup processes that show in yellow, and that seemd to work for a day or so. But this morning the problem is back.

If I can't work out anything software-wise, I'll do what you suggest. (BTW, if you flash the BIOS, are all user settings deleted, or kept?).

Thanks.

flashing the bios only overwrites any changes you've made to bios settings, which is usually very few as you only make them within bios itself. I would at least unplug and replug your usb devices

I have changes in the BIOS... if I am going to flash the BIOS I need to check what has changed! :)

How would I monitor what is happening at boot? Using Process Monitor doesn't really help, as the programmes that show long durations are no duobt hanging because of this issue, rather than being the causes of it. Disbaling them at startup doesn't help anyway, so...

The xperf results may show what I need to know, but I don't know how to interpret them in such a way as to be able to say 'yes, that is what is causing the delay'.. I may be wrong, but I have a strong feeling that this is a software issue, but I don't want to do anything too drastic just yet. (I have an image of the C drive I could reinstall, but I have had enough failed drive image reinstallations to put me off doing this except as a last resort).

Depending on where a problem is on a hard drive, you can run great in windows but have a problem when loading its driver at startup. If I were in your shoes, I'd clone the boot drive onto a different drive then swap the drives, because it sounds like your hard drive is probably the issue, assuming you have tried to boot without usb devices, or at least swapped their ports. My two cents

You can determine if the problem is related to an installed application by booting into safe mode.
If you can reproduce the problem when booting into safe mode, it means that the problem
is likely related to the windows startup process, drivers, or hardware. If the problem only appears
when you boot normally, it's probably related to one of your installed application programs failing to
start correctly.

Thanks for the comments. A gut reaction tells me that it is a software issue, yes: a programme waiting to load that fails to do so, as you say Charles. If it were hardware related, I wouldn't expect certain programmes to run fine and others not. If I open Task manager whilst the 'semi freeze-up' is current, it has relatively few processes showing. When the freeze-up stops, usually 30 seconds or so after the desktop appears, many more applications show up all of a sudden in TM.

Obviously, I need to do quite a bit more troubleshooting, but it involves many many boots and reboots and since the problem doesn't happen every time, it's quite a commitment, time-wise.

What would be really useful would be if some boot trace would indicate the process everything is waiting for! I did, as I say, try MSConfig a few times, but gave up when, even with startup items disabled, I got the freezing again after several successful boots (lots of red herrings!). maybe I need to disable Windows startup items too - I will find time (and, moreover, patience) to have a long session on this and report back...

(NB. I wonder if it is somehow a USB issue - I have had many problems with USB in the past, and over the past several weeks keep hearing the Windows USB disconnect tone for no apparent reason (no indication comes up of something having been disconnected). Another reason I suspect a USB issue is that I periodically get a message saying that connection to my CyberPower UPS (there a USB link for data) has been lost; it comes back several seconds later. No problems show in Device Manager, no red or yellow there. Again, that may all be a red herring though. What do you guys think?).

usb is unlike any other connector. The metal contact points and the variable snugness of the fit is poorer for usb than for all other connector types. This is to allow maximum ease in plugging things in and out, but it comes at a slight cost of electrical integrity. And just a tiny change to the pressure of the fit, or the humidity in the room, or the temperature, or invisible oxidation - any of these can change a one to a zero and corrupt the connection causing non-repeatable device detection/driver load problems and intermittent hangs. In all three of my posts so far I have mentioned usb yet it appears you have not tried swapping out the usb devices or at least switching their ports. Your symptoms are consistent with an intermittently failing usb connection or hard drive. Not sure what else to say.