I am upgrading from Lightroom 4 to Lightroom 6 and having problems with upgrading the catalog, The same question is repeated and additional copies are added but I cannot start using the software without this happening again. Any suggestions? I use Windows 7
Launch LR 6 and go to:
File >> Open Catalog
Then navigate to your LR4 catalog (default location is normally the Pictures folder) and choose (highlight) the named LR4 catlog and click open.
Let us know if you get any error message.