I believe aas of 12.x.x there was a new column added, called status.  That is not the status of the lcoator.  it is the status of any items in the locator.  Setting to inactive makes them non-transactable.  You must use the inactive on column and assign a date.  If you get this message --> "APP-INV-05530: Diasabling this locator can invalide other transactions which reference it" it means something is "holding" on the locator .

Check this:

You need to move inventory out of the locator. 

Make sure nothing else is pointing to the locator.  For example,  item locator assignements identify a primary locator for an item in a warehouse.  That must be removed. 

Any pending transacions must also be removed (e.g. pending cycle count, PO receipt that has not processed, etc.).

Use this query to check for pending transactions associated with the locator:

select * from mtl_material_transactions_temp where locator_id = &loc_id;

You will need the locator id.