When you install DbaBar, a message is displayed saying the installer cannot replace a certain file:


The installer tries to replace certain dll's needed to run DbaBar. If you still have open Internet Explorer sessions, this operation will fail.
You'll have to make sure all Internet Explorer sessions are closed. If you do not see any Internet Explorer sessions on the taskbar, but still are unable to replace the dll's when clicking the retry button, open the Windows Task Manager and manually kill the IEXPLORE.EXE processes by clicking the right mouse button and choose 'End Process'.