Once the installer has configured Microsoft Visual C++ you will need to restart your computer before the changes become effective. Once you have restarted your computer, launch the Matlab installer again, and the process should proceed as expected.

If that doesn't help, try restarting the machine in Safe Mode and running Microsoft Visual C++ Redistributable installer directly from /bin/win32/vcredist_x86.exe or /bin/win64/vcredist_x64.exe