SharePoint 2016 Product Configuration Wizard Error: Configuration Failed with Unauthorized Access Exception

If you are going to deploy SharePoint 2016, this is a common error that encountered.

The error pretty much pointing to a Access permission which you might doubtlessly think its database permission but no it’s not !

If you expand the event log, It will have 100, 104 errors logged due to this.

Resolution is to permit setup account to access Tasks folder (C:\Windows\Task). This is a critical folder which needs to be able to access by the setup account during the Product Configuration.

To take the ownership of this folder, log in to relevant SharePoint server using a local admin account and right click on the Tasks folder.

Under Security tab, go to Advance

Change the Owner from SYSTEM to your Setup account (the account will be used to run Product Config Wizard)

Once changed, the new owner can be seen as showed below.

Repeat the same for all SharePoint Servers in your farm if you planned to have multiple. Now run the Product Configuration Wizard again and you will notice its smoothly passing to task 5. within few minutes, the Wizard will be successfully complete.

And here comes the winning moment !

If you are still accounting with any additional errors in the Wizard, these points are some basic ones to verify.

Ensure:

1. Antivirus Disabled for all SharePoint and Database Servers (If any)
2. Firewall
3. Named Pipes in SQL Services enabled (Sometimes this isn’t enabled by default)

And then: