Freenas has detected partitions or zfs pools on new drives

[creative_username]

I'm replacing my drives in my server and using the freenas auto expand to grow the size of the array. Whenever I put my new drives in and go to the prompt to replace the missing disk, I get a warning message saying it has detected another partition or zfs pool; the only way I can replace the missing drive is if I check the "force" box. Before I put them in the server I tested these drives with seatools, afterwards I checked them with disk management on windows and "wiped" them using freenas gui. They have never been formatted.
Is this normal? I don't recall having to do this when I expanded my array fall last year.

Sorry if it's a stupid question.

 

[SweetAndLow]

What version of freenas

 

[creative_username]

What version of freenas

latest stable version of 9.10

 

[MrToddsFriends]

Windows disk management write a signature into the MBR. Can't say it for sure, but maybe this is the reason for the warning.

https://blogs.technet.microsoft.com/markrussinovich/2011/11/06/fixing-disk-signature-collisions/
(Section Disk Signatures)