This can sometimes happen after a windows update to a user's PC and the MSCOMCTL.ocx files needs to be re-registered. Prior to trying this ensure you use task manager and test to make sure the windows are not appearing off screen.
This file needs to be registered either locally on a users machine or if on a Shared server when everyone is logged off. To register the MSCOMCTL.ocx file please follow the steps below:
.
Connect to the affected user's machine.
Navigate to the SysWow64 folder and ensure the MSCOMCTL.ocx file is there, found in C:\Windows\SysWow64
Open Command Prompt as Administrator.
Open the SysWow64 folder location in Command Prompt. (type CD followed by the file path)
Type regsvr32 mscomctl.ocx and press enter.
Log back into Proclaim and test.