Error found in the xensource.log,
1. Look for stale/duplicate XenServer Tools SR by running below command,
# xe sr-list name-label="XenServer Tools"
You will now get an output with 2XenServer Tools SR as shown below in the screenshot,
2. Check for the pbd currently attached parameter to determine the duplicate XenServer Tools SR as shown in the below screenshot.
# xe pbd-list sr-uuid=<UUID of SR>
3.Once determined the duplicate XenServer Tools SR proceed to forget the same from the xapi database by running below command.
# xe sr-forget uuid=<UUID of SR>
Note: You can right click the Storage Repository on the XenCenter Interface and select Forget if it is an option.
ADDITIONAL RESOURCE
How to Remove a Storage Repository from XenServer
https://support.citrix.com/article/CTX131328