My Qt Creator installation on Windows 10 was having trouble with managing Subversion revisions. Creator was complaining it couldn’t find svnversion.exe, but other things had to be wrong, as it was unable to add/delete/rename SVN repo files properly. I figured the problem may be that Creator is a 32-bit application, and was unable to use SVN DLLs. I re-installed (TortoiseSVN), but since my OS is 64-bit, I had to install the 64-bit version. Then I noticed this on the download page:
Context menu in file-open/save dialogs on x64 OS
On x64 versions of Windows 7 and 8, the TortoiseSVN context menu and overlays won’t show for 32-bit applications in their file-open/save dialogs until you install the 2017 C-runtime for x86. (select the vc_redist.x86.exe file for download).
Note: this only applies to 32-bit applications on x64 OS. The Windows explorer is not affected by this.
So, I install the vc_redist.x86.exe and everything now works.