I had to rebuild my PC - now Tortoise cannot connect to an existing repository

[tin...@demler.net]

I've rebuilt my Windows 10 C: drive from scratch and reinstalled all applications. I had and have a repository on a different hard drive D:. I can create a new repository there but I cannot connect to one that already exists there. When I attempt to open a repository from a context menu in a folder containing working files I get a repository window with an error displayed:
Unable to connect to a repository at URL 'file:///D:/svn_repos/RFXtrx'
Unable to open repository 'file:///D:/svn_repos/RFXtrx'

Is this some kind of access problem that has to do with ownership?