MSMQ supports offline operations for applications running on independent client computers. While the client computer is offline, the application can still send and read messages from local queues. Messages sent while a computer is offline are stored locally, then sent to their final destination when the client computer is reconnected to the network.
Note Dependent client computers cannot be used for offline operations.
When operating offline, the application must avoid using any call that would need to access the MQIS. Any call to MQIS would attempt to generate network activity, causing an error or timeout.
The table below lists all the functions and methods that access the MQIS and cannot be called when operating offline.
| API Functions | ActiveX Methods |
| MQCreateQueue (for public queues) | Create (for public queues) |
| MQDeleteQueue (for public queues) | Delete (for public queues) |
| MQGetMachineProperties | MachineIdOfMachineName |
| MQGetQueueProperties | Refresh |
| MQGetQueueSecurity | IsWorldReadable |
| MQGetSecurityContext | AttachSecurityContext |
| MQLocateBegin | LookupQueue |
| Reset | |
| MQLocateNext | Next |
| MQOpenQueue (for public queues opened to receive messages) | Open (for public queues opened to receive messages) |
| MQPathNameToFormatName | |
| MQSetQueueProperties | Update |
| MQSetQueueSecurity |