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The first problem is most likely either a compatibility problem with the 2006 engine, or you’ve made a mistake in the VMF. ALT+P doesn’t search for every error possible, so you could use Interlopers compile checker, or search your recent changes yourself.
But the SDK 2007 issue is a simple fix. Have you MANUALLY configured BM for use in the SDK? This tutorial is good, and you should have zero problems
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That should just be your Steam\Steamapps%username%\half-life 2 folder. Because of Summer’s Steampipe update the exe is no longer there, but it should work fine regardless (or it does for me, anyway).
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Redoing your file in the 2007 engine would not help anything other than make you start again, which is clearly not ideal, nor is it necessary. Hammer is more or less the same between engines, so that’s not the issue.
The grid issue is from you not having 2007 Engine Branch properly configured for BM. In my experience, simply creating a new setup from within the SDK does not work, and just causes the grid problem.
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Probably did something incorrectly somewhere. Are you sure you’ve modified the correct file, and your syntax and everything is proper? If you copy-paste the contents of the file here (preferably in [code] tags) I can take a look.
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If that’s the %username%\sourcesdk\bin\source2007\bin\GameConfig.txt file, then yeah, that all looks fine.
Hmm. How’s the config inside of Hammer? Everything check out? Tools>Options…
Here’s mine, for example. Particularly important boxes in red.
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