Windows update failed to install with error code 80070026.
This issue can occur if one of the following factors is true:
1. Corrupted Windows Update temporary folder.
2. A Windows Update component is not working.
3. A system file is not working.
We can refer to the following steps to test our issue.
Suggestions 1: Rename the Windows Update temporary folders:
1. Click "Start", in "Start Search" item, type: "notepad" (without quotes) and press Enter.
2. Copy the following commands and then paste them into the opened Notepad window:
net stop wuauserv
net stop CryptSvc
ren %windir%\system32\catroot2 catroot2.old
ren %windir%\SoftwareDistribution sold.old
net start CryptSvc
net start wuauserv
3. After pasting the above commands, please close the Notepad window. Choose "Save" when you are prompted to save the file. Type "rename.bat" as the file name and save it to the Desktop.
4. Return to the Desktop, right click the rename.bat file and choose "Run as administrator".
5. You will see a DOS-like window processing.