Can Mathematica 9 peacefully coexist with Mathematica 8 on Windows?

Question

I am running Windows XP Professional (Service Pack 3). I am a graduate student, and my institution has a license for Mathematica for Students.

Back when Mathematica 8 was released, I was worried that (for whatever reason) I would not like it or that it would not run properly on Windows XP Professional, which is quite old by Windows standards. So, I tried to install Mathematica 8 in addition to Mathematica 7 which was also on the same computer. As it turned out, this worked fine; Mathematica 7 and Mathematica 8 simply peacefully coexist in different installation directories ($InstallationDirectory gives "C:\\Program Files\\Wolfram Research\\Mathematica\\7.0" in Mathematica 7, and $InstallationDirectory gives "C:\\Program Files\\Wolfram Research\\Mathematica\\8.0" in Mathematica 8; these are the default installation directories).

Now Mathematica 9 for Students is out and offered by my institution, and I am eager to try it because of the PlotLegends feature that has supposedly been much improved. But I would be very, very sad if installing Mathematica 9 somehow corrupted my existing Mathematica 8 installation, because there is a chance that my computer will be too slow to handle Mathematica 9, especially its supposedly "beefed up" front end, and I will need to revert to 8.

Do you have any experience with installing version 9 on the same computer as version 8? This previous question by another user discusses problems with installing a trial version of 9 next to genuine 8, which was apparently due to a bug. I am just curious if you have experience with installing genuine 9 next to genuine 8, and whether there is likely to be any overlap between system files/directories used by these two versions.

(I'm really only interested in version 9 because of the new PlotLegends, and that is the only reason I would like to try it. I would like to use Mathematica to generate publication-quality plots, but I can't really do this without some reasonably easy-to-use and easily reproducible PlotLegends.)

Answer 1

Oleksandr R. reports:

Yes; in general there is no problem with installing multiple versions at the same time. I have versions 5.2, 7.0.1, 8.0.4, and 9.0.1 installed on this computer (64-bit Windows 2003). You may prefer to keep the front end preferences separate for each version, otherwise they can confuse each other and reset themselves. Except for that, I've not noticed any problems.

Various users report success on XP, Vista and Windows 7.

About keeping preferences separate rm-rf writes:

You can find the option in Preferences > System . Alternately, make a backup of your FE's init.m (in $UserBaseDirectory/FrontEnd) and replace it with one that merely has the line

SetOptions[$FrontEnd, "VersionedPreferences"->True]. 

When you restart any version of Mathematica (or install a new version), it will automatically create a version specific init.m. You will however have to copy over/redo your customizations (if any).

I myself encountered a small problem: On our home pc we have two different licenses for 8 and 9, but installing 9 set the license number for my v8 to the one of my v9. Other than that, they are running both without problems.