Try the following....
Hold down Shift Key and restart computer.
Click on Troubleshoot, then Advanced Options.
Click on See More Recovery Options, then Startup Settings.
click on Enable Safe Mode, then click on Restart button on same page.
Can't you use msconfig to enter safe mode? in Run box type msconfig, then click on diagnostic startup. I never tried that in W10, only XP, so I don't know for sure that's the answer.
Here is a summary of how I understand your situation along with some comments
You have a 5 year old toshiba satellite c850d
--- Is this your computer?
Toshiba Satellite C850D-011 - 15.6" - E2 1800 - 4 GB RAM - 500 GB HDD - Canadian English/French
Toshiba Satellite C850D-011 Specs - CNET
CPU AMD E2 1800 / 1.7 GHz
The original OS was Windows 8
--- One of the original features it came with is Toshiba PC Health Monitor.
--- You can't get into yet because you can't log into Windows
--- However does Toshiba have a pre-boot diagnostic utility?
--- If so, try it.
Your issues are: Upon startup there isn't a Toshiba logo and the computer keeps looping with an alternating black screen/blue screen with solid cursor.
--- Coincidently this started after a after creator update fail.
--- Do mean from 1709 to 1803 and how long ago did the failed update occur?
You did start the computer w/o the HDD, put it back in.
--- Upon startup, this time you did get as far as the Toshiba logo but that's it.
--- If you can duplicate that, it might be a good time to see if you can get into Safe Mode
--- But then if you can't duplicate that try getting into Safe Mode again just the same
On how to get into Safe Mode
--- Instructions have been posted in post #2 by spunk & post #11 by dencal.
--- Have you tried either one or both of them?
On your InsydeH20 bios it is a UEFI BIOS, the good news is that you can boot into it.
InsydeH2O® UEFI BIOS | Insyde Software
--- In post #5 "The bios is set to slow boot, the boot is not slow."
--- Please ensure the BIOS is set to default settings.
--- Go back in set it to slow boot.
--- Also set it to disable Secure Boot.
A few other things you can do is disable fast boot if the above doesn't take effect but leave those settings there just the same.
Run powercfg.exe /hibernate off to eliminate FastBoot.
--- From what I understand FastBoot can bypass some of the normal Bios startup processes.
Visit Turn On or Off Fast Startup in Windows 10
Turn On or Off Fast Startup in Windows 10 | Windows 10 Tutorials
With all of that said, would you consider a clean install?
The OP that started this thread has not replied for approximately 10 weeks.
The problem may have been fixed?
I have had run into this problem:
Laptop Boots and a Stop Error code X (BSOD) - BSOD Code List is useful but not Important, or just want to get to into SAFE MODE -Holding the Shift Key, F8, Shaking it, lighting Sage and Chanting would not Boot into Windows, so could not run MSCONFIG, Shift +Restart Options,etc.
Toshiba and Microsoft will try to recover and won't start until it tries automatically. A good thing and bad thing, and when it fails to do so on their own it will turn it over to you. These are the screen option steps to get to Safe Mode.
TO BOOT INTO SYSTEM REPAIR AND THEN TROUBLESHOOT/ADVANCED DIAGNOSTIC TO GET TO SAFE MODE-
1. Press [Power Button] OFF (If On), then [Power BUTTON] ON - When the Toshiba Screen shows up, [Power BUTTON] OFF
On the 3rd Attempt, (or before) - "Preparing to Auto Repair, then Diagnosing ... and arrive at Blue screen, TO GET TO SAFE MODE:
Select [ADVANCED OPTIONS],
[TROUBLESHOOT],
[SEE MORE OPTION],
[STARTUP SETTINGS]-Change Startup Behavior.
The screen will describe the what Safe Mode settings
[RESTART]
On this Restart, you SHOULD Arrive at The Safe Mode you desperately seek.
If this it fails to Restart in Safe Mode, you have discovered the source of the problem. I disagree with nearly everything posted about what to do next, because it is complicated and not only didn't help, it caused more harm than good. Without venturing into those issues and going off topic, I offer the Safe Mode procedure which worked for me; I can share what worked beyond when Safe Mode boot didn't work or could not there using the above either.
Thank you for sharing what worked for you.
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