Not every version of VS works with every version of the framework. For example, VS2010 will work with framework versions up to 4.0. I would be surprised if VS2012, which was the very next version after VS2010, would work with FW4.8. It should run fine with that being on the computer, but it won't let you target that. Not every framework will work on every version of Windows, either. I didn't think that FW 4.8 would work with Windows 7, for example, so I'm a bit surprised that you were even able to install it. On the other hand, maybe it didn't work.

Personally, I have long felt, and still feel, that VS2012 was probably the worst version of VS ever released. It was ugly compared to the ones before or after, and added pretty much nothing. There are arguments against VS2015, as well, but VS2012 was still worse. One could also argue that VS2002 or VS2003 was worse, but they were not bad at the time they were released, they are just bad in comparison to later versions. The same could be said of VS2005, which was really quite nice for it's time. Thus I would say that VS2012 was the worst of them all. So, if you can move on, then move to VS2017 or VS2019. Otherwise, go back to VS2010, which may have been the most beautiful version.