Error "CWPCA8522E Application did not get installed" is displayed on Standard client when opening the users mailfile.
To fix shut down the Notes client and then delete the following folders under the Data folder:
Data\workspace\.metadata\.plugins\com.ibm.portal.app
Data\workspace\.metadata\.plugins\com.ibm.rcp.portal.app
Restart the Notes client.
Thanks to Stephan Bovet for his post on the 8.5 forum for this solution.