--- a/taskcluster/taskgraph/transforms/job/mozharness.py
+++ b/taskcluster/taskgraph/transforms/job/mozharness.py
@@ -203,23 +203,23 @@ def mozharness_on_windows(config, job, t
         'TOOLTOOL_REV': 'master',
     })
 
     mh_command = [r'c:\mozilla-build\python\python.exe']
     mh_command.append('\\'.join([r'.\build\src\testing', run['script'].replace('/', '\\')]))
     for cfg in run['config']:
         mh_command.append('--config ' + cfg.replace('/', '\\'))
     mh_command.append('--branch ' + config.params['project'])
-    mh_command.append(r'--skip-buildbot-actions --work-dir %cd:Z:=z:%\build')
+    mh_command.append(r'--skip-buildbot-actions --work-dir %cd:C:=c:%\build')
     for option in run.get('options', []):
         mh_command.append('--' + option)
 
     hg_command = ['"c:\\Program Files\\Mercurial\\hg.exe"']
     hg_command.append('robustcheckout')
-    hg_command.extend(['--sharebase', 'y:\\hg-shared'])
+    hg_command.extend(['--sharebase', 'C:\\builds\\hg-shared'])
     hg_command.append('--purge')
     hg_command.extend(['--upstream', 'https://hg.mozilla.org/mozilla-unified'])
     hg_command.extend(['--revision', env['GECKO_HEAD_REV']])
     hg_command.append(env['GECKO_HEAD_REPOSITORY'])
     hg_command.append('.\\build\\src')
 
     worker['command'] = [
         ' '.join(hg_command),