There is a file installed by Mathematica (on the mac it is inside a folder called Library) called mathpass. You could search for it.
You can open it with a text editor.
Each time that you install a version of Mathematica, a new license or activation code is written to the file. This file is shared by all versions of mathematica on your system.
When Mathematica starts up, it looks for a valid activation. It uses the first one it sees.
Theoretically, when your trial license for version 9 expires, Mathematica 8 will search and find your valid license for version 8.
I have a similar problem -- being a beta tester for Mathematica 10. When I crank up Mathematica 9, it is using the activation for v 10.
If you are concerned, you can edit mathpass to get rid of the trial activation. I believe that you could simply delete mathpass and when you start up version 8 again, simply reactivate it.
If you look at the Wolfram documentation for resetting Mathematica, it suggests that as a last resort, you can deleter the Mathematica folders in the two Library folders (the computer wide one and the user-specific one). Details vary by system. I had an issue recently where I had to do this, and when I restarted Mathematica 9, I had to re-activate, but it worked.
It should be possible to simply delete mathpass.
Check with customer service.
On Oct 9, 2013, at 2:11 AM, E. Martin-Serrano <eMartinSerrano@telefonica.net> wrote:
> Hi, > > Now, I have realized that the notebooks created and running under the V8 > paid version also display the legend Wolfram Mathematica - PRODUCT > TRIAL . > > So it is not only the Welcome Screen what has been contaminated by the > trial V9 version. > > De: E. Martin-Serrano [mailto:eMartinSerrano@telefonica.net] > Enviado el: martes, 8 de octubre de 2013 13:42 > Para: email@example.com > Asunto: Version 9 Trial contaminates Version 8 running paid version > > Hi, > > Last week, I downloaded and installed V9 Trial, which I have already > uninstalled after only three days. > > It seems that, somehow, V9 was, conflicting with V8, which is the version I > am currently running. I uninstalled the Trial V9 to check whether I could > find the conflicting points with the idea of reinstalling V9 again to > continue the V9 trial. > > However, to my surprise, after the V9 trial uninstallation, the former V8 > version Welcome screen is warning that my V8 paid Mathematica is =a trial > product and that there are 26 days left for it. > > I have used the Windows uninstall tool to get rid of Mathematica V9 Trial > and probably there are some leftovers still working in the original V8 > system (a clear indication of that V9 is interfering with the paid V8 even > after the trial V9 has been uninstalled). Besides, after finishing the > uninstallation, Windows8 warned it could not uninstall the whole > Mathematica V9 trial stuff so that I ought to move manually the trial V9 > kernel to the recycle bin. > > I hope someone could provide some clue about what is going on before the my > current 26 days v8 trial period is over > > Regards > > E. Martin-Serrano > __________________________________________ > > This e-mail and the documents attached are confidential and intended > solely > for the addressee; it may also be privileged. If you receive this e-mail in > error, please notify the sender immediately and destroy it. As its = > integrity > cannot be secured on the Internet, no sender=92s liability can be = > triggered > for the message content. Although the sender endeavors to maintain a > computer virus-free network, he/she does not warrant that this = > transmission > is virus-free and will not be liable for any damages resulting from = any > virus transmitted. > > Este mensaje y los ficheros adjuntos pueden contener informaci=F3n > confidencial destinada solamente a la(s) persona(s) mencionadas > anteriormente y su contenido puede estar protegido por secreto = > profesional y > en cualquier caso el mensaje en su totalidad est=E1 amparado y = > protegido por > la legislaci=F3n vigente que preserva el secreto de las = comunicaciones, = > y por > la legislaci=F3n de protecci=F3n de datos de car=E1cter = personal. Si = > usted recibe > este correo electr=F3nico por error, gracias por informar = > inmediatamente al > remitente y destruir el mensaje. Al no estar asegurada la integridad = de = > este > mensaje sobre la red, el remitente no se hace responsable por su = > contenido. > Su contenido no constituye ning=FAn compromiso para el remitente, = salvo > ratificaci=F3n escrita por ambas partes. Aunque se esfuerza al = m=E1ximo = > por > mantener su red libre de virus, el emisor no puede garantizar nada al > respecto y no ser=E1 responsable de cualesquiera da=F1os que = puedan = > resultar de > una transmisi=F3n de virus. > > >