Windows Upgrade Error Codes Decrypted

So you tried to upgrade your Windows machine to Windows 10 and it did not work. Got the cryptic error code 0x80070070 thrown at you, for instance when you check the Event Viewer, but have no idea what it means.

A search on the Internet shows that other users experienced the same issue, but most of what is suggested is guesswork.

Did you know that these error codes follow a specific pattern that you can easily decrypt? It is actually pretty easy provided that you know where to look for the information.

Lets take 0x80070070 again and see where it takes us. The two important bits that you need to extract from the error code are the first number after the x, and the last four digits.

Windows Upgrade Error Codes Decrypted

The first number indicates the error code type. An 8 means it is a Win32 error code, a C means it is an NTSTATUS value.

Once you know that, you simply look it up either on the Win32 error code page in the case of a Win32 error, or on the NTSTATUS page instead.

Since the example error code refers to a Win32 error code, you would look it up on the Win32 error code page. There you would find listed 0070 which indicates a disk space error.

To sum it up:

1. Check the first number after the 0x to find out whether it is a Win32 or NTSTATUS error.
2. Consult the error code page that resulted from 1, and look up the last four digits on the page to find out what the error code means.

The error type is listed on the page, and a description that is often more useful as it provides you with additional information.

Not all error codes or descriptions are easy to understand though, and you may not know what you need to do to resolve it after identifying the error correctly.

While error codes like 0003 path not found or 004 access denied may point you in the right direction, codes like 00D7 nesting not allowed or 00D1 the signal number is invalid may not.

Still, knowing what an error code means can provide you with valuable information on where to look for help. Even if you cannot figure it out on your own, you may provide others with the additional details as they may have a fix for that issue.

Obviously, this won't help you if a patch or update is borked and needs updating by Microsoft first.

In case you are wondering, the information come from a detailed article on Microsoft's IT Pro website over on Technet that explains how to resolve Windows 10 Upgrade Errors. It is a good read and well worth a bookmark; while designed for Windows 10, it may prove useful for previous versions of Windows as well.

There is a list of common errors, explanations, and mitigation instructions. This includes error codes 0xC1900101, and various 0x800xxxxx error codes which can be really useful especially when upgrading a system to Windows 10.

In case you are interested in generic Windows Update error codes and their meaning, check out this resource page on the Microsoft website instead.

Now You: How do you handle Windows update or upgrade errors?

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