This video shows you how you can easily resolve blue screen error of this particular error code: 0xc000021a. This type of error is commonly caused by interrupting Windows Update. That is when your Computer looses power while trying to install windows update.
Using window’s Automatic Repair feature doesn’t solve the problem, neither does System restore resolve the problem. The only workable solution is using The Deployment Image Servising & Management Tool – DISM via Command prompt. Enter the following code into command prompt to revert any pending actions;
dism /image:c: /cleanup-image /revertpendingactions