Created attachment 106752 [details] log-C_KDE_.txt (compressed). Sorry for the bug reports. All of these issues are from an installation which previously produced KDevelop binaries.
Did you check what the error message told you? What value does this have in kdesettings.ini: [Paths] PYTHON27
I found two kdesettings.ini files, one in C:\KDE\craft and one in C:\KDE\etc. Which do I need to modify? The one in C:\KDE\etc has a path for "Python" that points into C:\KDE. For both the commented line for Python27 sets a value of C:\Python27, which isn't in the KDE root. KDE installed Python 3.6 itself, do I need to install Python 2.7 manually? Why? Why did I not receive this error before?
> I found two kdesettings.ini files, one in C:\KDE\craft and one in C:\KDE\etc. Which do I need to modify? The one in C:\KDE\etc has a path for "Python" that points into C:\KDE. You need to modify the one in C:\KDE\etc\. The other one is just a template. > KDE installed Python 3.6 itself, do I need to install Python 2.7 manually? Yes, I think you need to install that by yourself. @Hannah: Or is that not true? > Why did I not receive this error before? It looks like you're attempting to build KDevelop. In craft's master branch, KDevelop just started to depend on the QtWebEngine package, which requires Python2.