Error destroying zpool

[subsies]

I am trying to remove a zpool with the following command:

zpool destroy DataStore

The following is the output of that command

cannot unmount '/mnt/DataStore/.system/syslog': Device busy
could not destroy 'DataStore': could not unmount datasets

Upon revision, I verified that a different pool has been set as the system dataset pool. How can I remove the zpool making sure I don't mess up my installation?
Screenshot of configuration

 

[SweetAndLow]

Don't use the cli, use the gui with freenas. You might need to move the system dataset to the boot drive. Read the manual for how to do that.

 

[subsies]

Don't use the cli, use the gui with freenas. You might need to move the system dataset to the boot drive. Read the manual for how to do that.

Using the GUI is not an option as it is not working properly.

 

[SweetAndLow]

Using the GUI is not an option as it is not working properly.
View attachment 47568

What version and fix your gui problems.

 

[subsies]

9.2.1.6-BETA
Was going to upgrade to RELEASE but am not certain if the zpools are encrypted or not, as I did not set up this machine.