Delphi 2010 can't upgrade Delphi 2007 projects

If I open any of my Delphi 2007 projects in Delphi 2010 it prompts me that it will upgrade it. Unfortunately, that leaves Delphi 2010 to give errors about not knowing where to find system and other core units. On the other hand, if I delete all the BDS project files and only leave the .dpr, Delphi 2010 can successfully open and compile my project. 

However, besides that quirk, I have another problem. I need to have both a working Delphi 2007 project and Delphi 2010, so I can compile using both without being prompted each and every time about upgrading project :)

So... Any ideas to what might be the cause of the problem? And how do you ensure you can compile using both development environments?
Can I move the BDS specifc project files to own directories (one for D2007 and one for D2010?) Or should I rename the D2007 BDS project files myself? And then let D2010 open the .dpr file? I'm thinking that might work, I will just need to "touchup" the Delphi 2007 BDS projects files then with correct file name info.

> {quote:title=Thomas Schulz wrote:}{quote}
> If I open any of my Delphi 2007 projects in Delphi 2010 it prompts me that it will upgrade it. Unfortunately, that leaves Delphi 2010 to give errors about not knowing where to find system and other core units. On the other hand, if I delete all the BDS project files and only leave the .dpr, Delphi 2010 can successfully open and compile my project. 
> 
> However, besides that quirk, I have another problem. I need to have both a working Delphi 2007 project and Delphi 2010, so I can compile using both without being prompted each and every time about upgrading project :)
> 
> So... Any ideas to what might be the cause of the problem? And how do you ensure you can compile using both development environments?
> Can I move the BDS specifc project files to own directories (one for D2007 and one for D2010?) Or should I rename the D2007 BDS project files myself? And then let D2010 open the .dpr file? I'm thinking that might work, I will just need to "touchup" the Delphi 2007 BDS projects files then with correct file name info.


I don't kno wabout d2007, but I have D7 and now d2010. I have copied my projects to a folder just for d2010 so the D7 source etc is still the same. This has been useful because one project doesn't give the same results when compiled in d2010 as in D7 and untill I can work out how to fix it I am still compiling and updating the D7 version. If I had tried changing the source for d7 with d2010 I would have ended up not being able to get a working result with either unless I restored backups.

> {quote:title=Thomas Schulz wrote:}{quote}
> If I open any of my Delphi 2007 projects in Delphi 2010 it prompts me that it will upgrade it.

The popular advice through the years has always been to NEVER rely on that feature.  It has never worked reliably, in any version.  ALWAYS create a new project fresh and add your existing source files to it as needed.

> I need to have both a working Delphi 2007 project and Delphi 2010, so I can compile using
> both without being prompted each and every time about upgrading project :)

All the more reason to create a separate 2010 project, and just have the two share source files (you have to be careful about 2010 adding new properties to your DFMs that 2007 will error on, though).

--
Remy Lebeau (TeamB)

Thanks everyone. I got it working now :)