If a CPMI (or equivalent mirror transaction) task locks in your CICS® region, it is possibly because you have reached the MAXTASKS limit of your CICS region. This prevents the mirror program from sending data back to the Client daemon, which appears to hang. The problem typically occurs when CICS has a high number of concurrent transactions. A solution is to put the mirror transaction in a TranClass that has a MAXACTIVE lower than the MAXTASKS of your CICS region. All new requests to the CICS region are queued, and CICS can continue to process current requests. The value you specify for MAXACTIVE depends on your installation, and other tasks running in the region.