A likely cause is that MSP crashed and the add-in has been unloaded by Microsoft Project as a precaution measure so that the program can be started normally.
The CA PPM Addin for Microsoft Project is missing in MSP and is listed under the Disabled or Inactive Application Add-Ins (under File - Options - Addins).
A likely cause is that MSP crashed and the add-in has been unloaded by Microsoft Project as a precaution measure so that the program can be started normally.
If disabled:
If inactive:
Clarity and MSP integration known defects - Support Technical Document Index (KB: 15956)
Clarity and MSP integration - List of knowledge documents (KB: 71385)