When trying to generate a file or some other output, the build fails with a "No space left on device" error.
All Virtual Machines have 200GB storage space by default. The preinstalled tools take up space varying amounts of space, on the latest Xcode stacks you should see 84GB free storage space for you to use, while Visual Studio for Mac based stacks only have about 50-60GB, due to having more tools pre-loaded on them.
We're continuously working on providing more storage, but as a short term solution, we recommend removing tools from the machine in Script step that take up place but are not being used.
Below you can find an example script that removes android sdk/ndk tools and certain simulator runtimes:
#fail if any commands fails
sudo rm -rf ~/Library/Developer/Xamarin/android-sdk-macosx
sudo rm -rf /usr/local/share/android-sdk
sudo rm -rf /opt/android-ndk
sudo rm -rf /Library/Developer/CoreSimulator/Profiles/Runtimes/iOS\ 11.*