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 Integration' Addin for Microsoft Project (MSP) is missing in MSP and is listed under the Disabled or Inactive Application Add-Ins (under File - Options - Addins).
What are the steps to enable the addin so that it will again be available on the toolbar?
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.
See also: