How to find an inactive vendor
Once a vendor is made inactive by marking the inactive box at the bottom of the Vendor record in the General Tab, it will no longer display in the Quick Find window. You must instead use the Find Vendor option and mark the box at the bottom left to display inactive vendors. See the screen shots below for the details.
Now that the vendor is inactive, they do not display in the Quick Find window.
In order to see them you must go to Vendors → Find Vendor (not Quick Find). Find vendor is on the top left of the Vendor Information screen.
The screen displays only Active vendors
Scroll all the way to the bottom of the screen and check the box, "show inactive vendors" and you should be able to find the vendor in Find Vendors or Quick Find.
When you go to Find Vendor you will see both active and inactive vendors.
Reactivating a Vendor: uncheck the inactive button on the vender under the Vender Information screen and click Submit to make the vendor active again.