If STMS import queue is locked

Import queue is locked without manual intervention and remains locked.

Below are reasons:

A STOPMARK can be called in a number of ways :

(a) Manually via STMS by choosing Queue -> Close.
(b) Manually via the OS level with command tp setstopmark <SID>.
(c) If you have not set the STOPMARK before starting an import then tp will automatically execute this command and place a STOPMARK at the end of the existing import queue right after the import command has been issued.

You can solve using below

To remove the STOPMARK (manually) then you chose via STMS, Queue -> Open. The OS equivalent is the command tp delstopmark <SID>. This command is normally not needed as tp will automatically remove the marker after an import process has been successfully completed.

If one remains then it means the import process has not completed successfully. Please check for running tp processes and any running imports in the import monitor.

Alternatively a STOPMARK can remain in the import queue if you previously performed an import all with the option "Select All Requests for Later Import".
 In this case all transport requests are marked with umode I, and the STOPMARK is not removed so that you can import the same set of transport requests into another client.