Issue with booting the computer and receive error code OXC000021a.

Hi,

Thank you for posting in Microsoft Community!

It seems like you have an issue with booting the computer and receive error code OXC000021a.

I understand that it must be frustrating, but rest assured, we are here to help and guide you in the right direction.

I may need a few more information to understand the issue better 1. Did you make any recent changes on the computer prior to this issue?

2. Are you using Tablet PC?

Method 1:

Let's first try to boot the computer to Safe Mode and check if you face the issue.

a. Boot from the Windows 8 DVD. ****b. Swipe on Repair your computer.

c. Swipe on Troubleshoot and then select Advanced Options.

d. Select the option Safe mode and check if the issue persists.

Note: I would suggest you to disconnect all external devices except mouse and keyboard and check if it helps.

Method 2:

Perform clean boot if the issue does not occur in Safe Mode. Set the computer in ‘Clean boot’ state to check software conflicts. Refer the following steps:

Step 1:

a) Swipe the ‘Windows + R’ key on the keyboard.

b) In the ‘Run’ windows type ’MSCONFIG’ and click ‘Ok’.

c) Swipe the ‘Boot’ tab and uncheck ‘Safe Boot’ option.

d) On the ‘General’ tab, swipe to select the option ‘Selective startup’, and then swipe to clear the option Load startup items check box.

e) On the ‘Services’ tab, swipe to select the ‘Hide all Microsoft services’ check box, and then click ‘Disable all’.

f) On the ‘StartUp’ tab, swipe ‘Open Task Manager’. In the Task Manager window under startup tab, swipe on each startup item which are enabled and select ‘Disable’.

g) Swipe ‘OK’, and then swipe Restart.

Step 2: Enable half of the services:

a. Follow steps 1a and 1b to start the System Configuration utility.

b. Swipe the Services tab, and then swipe to select the Hide all Microsoft services check box.

c. Swipe to select half of the check boxes in the Service list.

d. Swipe OK, and then swipe Restart.

Step 3: Determine whether the problem returns:

If the problem still occurs, repeat step 1 and step 2. In step 2, swipe to clear half of the check boxes that you originally selected in the Service list.

If the problem does not occur, repeat step 1 and step 2. In step 2, select only half of the remaining check boxes that are cleared in the Service list. Repeat these steps until you have selected all the check boxes.

If only one service is selected in the Service list, and you still experience the problem, the selected service causes the problem. Go to step 6. If no service causes this problem, go to step 4.

Step 4: Enable half of the Startup items: ****If no startup item causes this problem, a Microsoft service most likely causes the problem. To determine which Microsoft service may be causing the problem, repeat step 1 and step 2 without selecting the Hide all Microsoft services check box in either step.

Step 5: Determine whether the problem returns:

If the problem still occurs, repeat step 1 and step 4. In step 4, click to clear half of the check boxes that you originally selected in the Startup Item list.

If the problem does not occur, repeat step 1 and step 4. In step 4, select only half of the remaining check boxes that are cleared in the Startup Item list. Repeat these steps until you have selected all the check boxes.

If only one startup item is selected in the Startup Item list, and you still experience the problem, the startup item that is selected in the list is the service that is causing the problem. Go to step 6.

If no startup item causes this problem, a Microsoft service most likely causes the problem. To determine which Microsoft service may be causing the problem, repeat step 1 and step 2 without selecting the Hide all Microsoft services check box in either step.

Step 6: Resolve the problem:

After you determine the startup item or the service that causes the problem, contact the program manufacturer to determine whether the problem can be resolved. Or, run the System Configuration utility, and then click to clear the check box for the problem item.

Step 7: **** Note: After you have finished troubleshooting, follow these steps to boot to normal startup.

a) Swipe the ‘Windows + R’ key on the keyboard.

b) In the ‘Run’ windows type ’MSCONFIG’ and swipe ‘Ok’.

c) On the ‘General’ tab, swipe the ‘Normal Startup’ option, and then click ‘OK’.

d) Restart the computer and check with the issue.

Method 3:

If the issue persists, you may try to perform Automatic repair from Windows Recovery Environment (WinRE).

To perform Automatic repair on Windows 8 computer follow these steps:

a) Insert the media such as (USB or DVD) and restart the computer.

b) Swipe F12 key (typically this is F12, but it can differ between computer manufacturers) and choose the drive that you inserted the installation media into.

c) Once the Windows Setup window appears, follow these steps:

d) Swipe Next and select Repair your computer.

e) You will then see a blue screen and an option to choose.

e) Choose the option Troubleshoot and select Advanced options. ****f) You may choose Automatic Repair from Advanced boot option.

Do get back to us and let us know the status of the issue, I will be glad to help you further. We, at Microsoft strive towards excellence.

my windows 8 (WIN7 WORKS FINE : MULTIBOOT) dont boot up ,it just shows black screen after the winlogo disappears.BUT I THINK I GET Oxc000021a ERROR AND CRASH DUMP WHILE I USE LAST USED GOOD CONFIGURATION . PLS CHECK THIS MINIDUMP UPLOADED IN SKYDRIVE

I have just come across error Oxc 000021a when I tried to do a windows 8 update on my Acer laptop. Unfortunately I don't have any boot up discs as windows 8 was pre-installed. I get a message saying automatic repair couldn't repair the pc. Can anyone help

Geoff

Hi there!

I was having this same problem. It may have something to do with the Windows update. I have tried everything that was recommend and the problem didn't go away updating NVIDIA driver, running the command prompts, etc).

In my case the problem was related to AVAST, even if you are not using it as your antivirus it may still be in your computer. You need to uninstall AVAST, but it won't work from the normal 'uninstall programs'. Check on google for how to uninstall AVAST and download the file called AVASTCLEAR. It will restart the computer in safe mode and perform the uninstall. That was it for me, I don't have the problem anymore.

I upgraded from windows 8 to 8.1 and kept getting the 0xc000021a error. It would crash citing this error and restart, usually that would fix the problem and it would start OK next time. I tried to get my printer working with 8.1 as it was not and I also used driver max to update drivers that may have  caused the problem. Now when I boot up the automatic repair comes on and mover to a screen where it asks me to choose my keyboard, but nothing works on the screen - , keyboard, mouse, tries other wireless mouse and keyboard and mouse with cable.

I went into recover and it says there is no restore point, but I know I set one a few days ago when I was using driver max software. The only other option is factory setting. I won't let me do a backup either, although the one I have will be reasonably recent. the only option I know left is a factory reset, but I don't want to do that unless it is really necessary. The reset takes me back to windows 7 too.