Unable to create working directory on Mac external drive

[Colin Cuthbert]

Bamboo version 6.9.1 running on Linux
Agent is 2014 Macbook Pro running macOS 11.6

I recently got an external thunderbolt 2 SSD and have set bamboo up to put the working directories on it.

The ext SSD is set up as HFS+ and the user that runs the bamboo agent process has read and write access to the drive.

When I run a build, I get this error when trying to clone the repo onto the ext SSD.

java.lang.RuntimeException: Unexpected exception
	at com.atlassian.bamboo.util.BambooObjectUtils.asRuntimeException(BambooObjectUtils.java:119)
	at com.atlassian.bamboo.v2.build.task.InitializeBuild.prepareWorkingDirectory(InitializeBuild.java:118)
	at com.atlassian.bamboo.v2.build.task.InitializeBuild.doCall(InitializeBuild.java:81)
	at com.atlassian.bamboo.v2.build.task.InitializeBuild.call(InitializeBuild.java:61)
	at com.atlassian.bamboo.v2.build.agent.DefaultBuildAgent.executeBuildPhase(DefaultBuildAgent.java:204)
	at com.atlassian.bamboo.v2.build.agent.DefaultBuildAgent.build(DefaultBuildAgent.java:171)
	at com.atlassian.bamboo.v2.build.agent.BuildAgentControllerImpl.lambda$waitAndPerformBuild$0(BuildAgentControllerImpl.java:131)
	at com.atlassian.bamboo.variable.CustomVariableContextImpl.withVariableSubstitutor(CustomVariableContextImpl.java:185)
	at com.atlassian.bamboo.v2.build.agent.BuildAgentControllerImpl.waitAndPerformBuild(BuildAgentControllerImpl.java:125)
	at com.atlassian.bamboo.v2.build.agent.DefaultBuildAgent$1.run(DefaultBuildAgent.java:127)
	at com.atlassian.bamboo.utils.BambooRunnables$1.run(BambooRunnables.java:48)
	at com.atlassian.bamboo.security.ImpersonationHelper.runWith(ImpersonationHelper.java:26)
	at com.atlassian.bamboo.security.ImpersonationHelper.runWithSystemAuthority(ImpersonationHelper.java:17)
	at com.atlassian.bamboo.security.ImpersonationHelper$1.run(ImpersonationHelper.java:41)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.io.IOException: Unable to create directory /TRANSCEND/UsersExt/amuzo/bamboo_build_dir/OIPRAF-IOS-JOB1
	at org.apache.commons.io.FileUtils.forceMkdir(FileUtils.java:2491)
	at com.atlassian.bamboo.v2.build.task.InitializeBuild.prepareWorkingDirectory(InitializeBuild.java:116)
	... 13 more

What do I need to do to fix/avoid this error?