# Building H2O¶

During the build process, the following error message displays. What do I need to do to resolve it?

Error: Missing name at classes.R:19
Execution halted


To build H2O, Roxygen2 version 4.1.1 is required.

To update your Roxygen2 version, install the versions package in R, then use install.versions("roxygen2", "4.1.1").

Using ./gradlew build doesn’t generate a build successfully - is there anything I can do to troubleshoot?

Use ./gradlew clean before running ./gradlew build.

I tried using ./gradlew build after using git pull to update my local H2O repo, but now I can’t get H2O to build successfully - what should I do?

Try using ./gradlew build -x test - the build may be failing tests if data is not synced correctly.