There is a thread here back in Feb 2018 about this exact problem.

That thread is too old to post to but the problem has not changed.
There is a limit of 13 characters for a folder name was the conclusion

I had to change this...

Z:\Src\boinc\win_build>buildenv type release platform x64
Initializing BOINC Build Environment for Windows
Software Platform Detected: Visual Studio 2013
Software NOT Detected: Build Tools...

to this...

c:\Src\boinc\win_build>buildenv type release platform x64
Initializing BOINC Build Environment for Windows
Software Platform Detected: Visual Studio 2013

While none of the above folder names exceed the 13 character limit mentioned in the original post, the drive "Z" is actually the network path
\\xxx\yyy\VS2013projects
so it seems the 14 character VS2013projects is not kosher even in a network path mapped as a drive letter.

FINALLY GOT A WIN BUILD!

2>------ Build started: Project: boinc, Configuration: Release x64 ------
…
2>  boinc_cli_vs2013.vcxproj -> c:\Src\boinc\win_build\.\Build\x64\Release\boinc.exe

As I said in that thread, I did update Compile Client for Windows with a note on that limitation. I feel your pain in discovering it afresh - it took me some time to work out what was going wrong, too!

As I said in that thread, I did update Compile Client for Windows with a note on that limitation. I feel your pain in discovering it afresh - it took me some time to work out what was going wrong, too!

I looked into this and the problem is actually the short name for the win_build. The "Z" would have worked OK.

I made an "issue" out of it and I suspect the "fix" is to just make another note on that wiki you listed above


https://github.com/BOINC/boinc/issues/3347