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1,Do you have multiple DPs in your environment. If yes, it seems that the client could not get the required applications from its DP during OSD. Please make sure that the boundary group is configured correctly and the applications are distributed to DPs associated to the boundary group. A similar thread for your reference, the solution is to distribute all the required applications to related DPs.
Sccm applications stuck in waiting to begin installation
2,If the issue persists, we can review below client logs to see if there is any further information: Smsts.log, CAS.log, AppEnforce.log and AppDiscovery.log. Refer to:
SCCM APPLICATION INSTALLATION WORKFLOW
Note: This is non-Microsoft link, just for your reference.
Hope it helps. Thanks for your time.
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