Dotnet 10 massively increased the build time vs dotnet 8

[Thullner]

I'n dotnet 8.0 the build time of our solution was around 40 seconds, (dotnet build), but after upgrading to dotnet 10 the build time has increased to around 120 seconds. We've tested it on multiple devices, but found this increase on each device.

We have around 200 projects in our solution but had no issues with this with dotnet 8.0.

Does anyone else have this issue?

[julealgon]

Does anyone else have this issue?

We've not experienced this with a similarly sized monolithic project (202 projects, mix of .NET10, .NET Standard 2.0 and .NET 472, including a WebForms project).

Build times have remained mostly the same I'd say (maybe ever so slightly faster after upgrading to VS 2026).

Since you are seeing this stark difference, I'd check binary MSBuild logs and look for any obvious differences there. I assume it could also be due to some source generator misbehaving.

[baronfel]

Definitely grab a binlog of a build with /p:ReportAnalyzer=true enabled - that will add diagnostic timing logs to all Csc build task invocations that can quickly point out of a specific analyzer is the cause of the increased build time. You can easily view binlogs with the log viewer at msbuildlog.com.