"Third Party Handler Error": "Unable to load: c:\Program Files\Corel\WordPerfect OfficeX\Programs\documentManagementHandler.dll"
To resolve this issue, follow these steps:
In the search box, type "regedit" and press Enter.
Click the > next to "HKEY_LOCAL_MACHINE".
Click the > next to "SOFTWARE".
Click the > next to "Wow6432Node".
Click the > next to "Corel".
Click the > next to "WordPerfect".
Click the > next to "16".
Highlight "Third Party".
On the right side, right click on "DLL1" and select "Rename".
Rename it to "DLL1old" and press Enter.
Close the Registry Editor and attempt to open WordPerfect.
It should now open without error.
Note: If there is no Corel folder under the Wow6432Node, just go through HKEY_LOCAL_MACHINE>SOFTWARE>COREL.