In my case, i have this error message : wuaueng.dll SUS20ClientDataStore: The version store for this instance (0) has reached its maximum size of 8Mb.
An issue was found here : EV100528
(Problem with wuaueng.dll SUS20ClientDataStore).
1. This error generally appears on a Client machine when they cannot connect to the information store on the server. Contact your System Administrator for more help.
The version store has reached its maximum size because of unresponsive transaction
If you are not connected to any server, you may try this step:
Register the Wuaueng.dll file
To register the Wuaueng.dll file, follow these steps:
a. Click Start, click Run, typeregsvr32 Wuaueng.dll, and then clickOK.
b. When you receive the following message, click OK:
DllRegisterServer in Wuaueng.dll succeeded.
2. Click on Start --> Run --> type in their services.msc
find and stop the Automatic Update service
then go to c:\windows\SoftwareDistribution folder and rename the folder DataStore
then follow the first step and restart the Automatic Update Service
** By doing this you may loose Update History but it will be ok and will rebuild during next update.