Visual Studio Long wait before Starting to build
I'd go to Tools -> Options -> Projects and Solutions -> Build and Run and then change the "MSBuild project build [output|build log] verbosity" to Diagnostic. At that level it will include timings which should help you track down the issue.
We had the same problem with an ASP.NET MVC web project running in Visual Studio 2013. We build the project and nothing happens for about a minute or so and then the output window shows that we are compiling.
Here's what fixed it... open the .csproj file in a text editor and set MvcBuildViews to false:
<MvcBuildViews>false</MvcBuildViews>
I had to use sysinternals process monitor to figure this out but it's clearly the cause for my situation. The site compiles in less than 5 seconds now and previously took over a minute. During that minute the Asp.net compilation process was putting files and directories into the Temporary Asp.net Files folder.
Warning: If you set this, you'll no longer precompile your views so you will lose the ability to see syntax errors in your views at build time.
There is the possibility that you are suffering from VS inspecting other freshly built assemblies for the benefit of the currently compiling project.
When an assembly is built, VS will inspect the references of the target assembly, which if they are feshly built or new versions, may include actually loading them in a .Net domain, which bears all the burdens of loading an assembly as though you were going to run it. The build can get progressively slower as it rebuilds more and more projects. When one assembly becomes newer the others do a lot more work. This is one possible explanation for why building by itself, versus already built, versus building clean, all have seemingly relevantly differing results. Its really tht the others changed and not about the one being compiled.
VS will 'mark down' the last 'internal' build number of the referenced assembly and look to see if the referenced assembly actually changed as it rolls through its build process. If its not differnt, a ton of work gets skipped. And yes, there are internal assembly build numbers that you dont control. This is probalby not in any way due to the actual c# compiler or its work or anything post-compile, but pre-compile steps necessary for the most general cases.
There are several reference oriented settings you can play with, and depending on your dev, test, or deployments needs, the functional differences may be irrelevant, however may profoundly impact how VS behaves and how long it takes during build.
Go to the references of one of the projects in Solution Explorer:
1) click on a reference
2) open the properties pane if its not (not the Property Pages or the Property Manager)
3) look at 'Copy Local', 'Embed Interop Types', 'Reference Output Assembly'; those may be very applicable and probably something good to know about regardless. I strongly suggest looking up what they do on MSDN. 'Reference Output Assembly' may or may not show in the list.
4) unload the project, and edit the .proj file in VS as text. look for the assembly reference in the XML and look for 'Private'. This means whether the assembly referenced is to be treated as though its going to be a private assembly from the referencing assemblies perspective, vs a shared one. Which is sort of a wordy way of saying, will that assembly be deployed as a unit with the other assemblies together. This is very important toward unburdening things. Background: http://msdn.microsoft.com/en-us/magazine/cc164080.aspx
So the basic idea here is that you want to configure all of these to be the least expensive, both during build and after deployment. If you are building them together, then for example you probably really don't need 'Copy Local'. Id hate to say more about how you should configure them without knowing more about your needs, but its a very fine thing to go read a few good paragraphs about each. This gets very tricky however, because you also influence whether VS will use the the stale old one when resolving before the referenced one is rebuilt. As a further example explaiing that its good to go read about these, Copy Local can use the local copy, even though its stale, so having this set can be double bad. Just remember the goal at the moment is to lower the burden of VS loading newly built assemblies jsut to compile the others.
Lastly, for now, I can easily say that hanging for only 1.5 mins is getting off very lucky. There are people with much much worse build times due to things like this ;)
Some troubleshooting idea's that have not been mentioned:
Clean solution?
Delete Obj and Bin folders plus the .suo file? FYI, neither Clean nor Rebuild will delete non-build files, eg files copied during a pre-build command.
Turn off VS scanning outside files. Options > tools > environment > document > detect when file is changed outside the environment?
Rollback SVN history to confirm when it started to occur? What changed? If the project file on day 1 takes the same time, recreate the project, add all the files and build.
Otherwise could you please run Process Monitor and let us know what Visual Studio is doing in the prep-build stage?