Source Build is always breaking?

Every day I have to re-download the source files and install dependencies because every new day, for some reason, like clockwork… I get these errors.

Error 1 Could not copy the file “obj\Development\UnrealBuildTool.exe” because it was not found. UnrealBuildTool

Error 2 error MSB3073: The command “…\Build\BatchFiles\Build.bat UE4Editor Win64 Development” exited with code 999. C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V120\Microsoft.MakeFile.Targets 38 5 UE4

Despite it working like a charm the previous days whenever I have to rebuild. Even restarting the computer etc… its every 8 hours later… it just…breaks?

I figure I have to be doing something wrong at this point so I’ve come to the answer hub for help because this is getting annoying…

I’m just trying to run the UE4 source build from VS2013 express…

Hi Demoneyejin,

This definitely sounds unusual. When you are getting these errors, are you trying to build the Engine or a game project?

Are you launching the Editor through Visual Studio’s debugger, or do you use the UE4Editor.exe file that is created when you built the Engine?

Well I know this issue usually comes up whenever I open up the source ue4 in vs2013 express and I try launching the ue4 solution via the development editor.

Through the visual studios debugger.

You should not need to launch the Editor through Visual Studio’s debugger. Using the executable created when you build the Engine will usually work better for most people. You can find the executable here: \Engine\Binaries\Win64

If you are opening a project, then you can use the Visual Studio debugger for that as long as your are not also building the Engine again.

Regarding the issue you are experiencing, you mentioned it is happening to you every few hours? If you build the Engine and then do nothing with it for a full day, don’t even open the solution in Visual Studio, does the issue still occur?

Yes. I built it last night so that I can follow along with the C++ tutorials this morning. tried creating my first actor class via the editor. got an error. Read online that I should open my project via the main source build,using the vs debugger. ran into the issue. the previous times, usually would happen after I created or worked on a project extensively…but on the same day closing and re opening the editor in the same way yielded no problems. the next day, I receive the errors listed above.

My theory is that my Anti Virus is removing that file, either after a certain time when it probably does a silent scan of my PC (which would make sense considering the long time between breaks. )

The only issue I have with that theory is that I have my Anti Virus set to exclude (from scanning ) the source build folder and the projects folder, but just thought I’d toss that out.

It is possible that this may be related to Anti-Virus software doing something unexpected. Unfortunately I cannot provide much support in that area. One thing you can try though, would be to rebuild the Engine so that it works, then have your Anti-Virus software run a scan through the Unreal Engine folder to see if it throws up any false-positive results.

Have you noticed if this seems to be occurring at approximately the same time every day? For example, do you always notice the errors in the morning when you first try to build a project?

Sorry for the late reply and again thank you for your patience to help me with my problem. I deactivated my Anti Virus and noticed that the problem disappeared.

I then re-activated my anti virus and the problem returned, so yes my Anti Virus was the source of my problems.

I did scan the folder but no false positives were reported oddly enough. My Anti Virus must be preventing the compiler from accessing certain files…The anti virus I use is Avast but was recommended to switch to another “more capable” AV.

I’m glad to hear that things seem to be working more smoothly for you. Anti-virus software can often be something of a wild card in these situations. Please let us know if you run into any other issues.