--- a/tools/tryselect/selectors/fuzzy.py
+++ b/tools/tryselect/selectors/fuzzy.py
@@ -193,17 +193,17 @@ def run_fuzzy_try(update=False, query=No
 
     if not fzf:
         print(FZF_NOT_FOUND)
         return
 
     vcs = VCSHelper.create()
     vcs.check_working_directory(push)
 
-    all_tasks = generate_tasks(parameters, full)
+    all_tasks = generate_tasks(parameters, full, root=vcs.root)
 
     key_shortcuts = [k + ':' + v for k, v in fzf_shortcuts.iteritems()]
     cmd = [
         fzf, '-m',
         '--bind', ','.join(key_shortcuts),
         '--header', format_header(),
         # Using python to split the preview string is a bit convoluted,
         # but is guaranteed to be available on all platforms.

--- a/tools/tryselect/tasks.py
+++ b/tools/tryselect/tasks.py
@@ -28,36 +28,36 @@ in your working copy:
     {}
 
 To fix this, either rebase onto the latest mozilla-central or pass in
 -p/--parameters. For more information on how to define parameters, see:
 https://firefox-source-docs.mozilla.org/taskcluster/taskcluster/mach.html#parameters
 """
 
 
-def invalidate(cache):
+def invalidate(cache, root):
     if not os.path.isfile(cache):
         return
 
-    tc_dir = os.path.join(build.topsrcdir, 'taskcluster')
+    tc_dir = os.path.join(root, 'taskcluster')
     tmod = max(os.path.getmtime(os.path.join(tc_dir, p)) for p, _ in FileFinder(tc_dir))
     cmod = os.path.getmtime(cache)
 
     if tmod > cmod:
         os.remove(cache)
 
 
-def generate_tasks(params=None, full=False):
+def generate_tasks(params, full, root):
     params = params or "project=mozilla-central"
 
     cache_dir = os.path.join(get_state_dir()[0], 'cache', 'taskgraph')
     attr = 'full_task_set' if full else 'target_task_set'
     cache = os.path.join(cache_dir, attr)
 
-    invalidate(cache)
+    invalidate(cache, root)
     if os.path.isfile(cache):
         with open(cache, 'r') as fh:
             return fh.read().splitlines()
 
     if not os.path.isdir(cache_dir):
         os.makedirs(cache_dir)
 
     print("Task configuration changed, generating {}".format(attr.replace('_', ' ')))
@@ -66,17 +66,17 @@ def generate_tasks(params=None, full=Fal
         params.check()
     except ParameterMismatch as e:
         print(PARAMETER_MISMATCH.format(e.args[0]))
         sys.exit(1)
 
     cwd = os.getcwd()
     os.chdir(build.topsrcdir)
 
-    root = os.path.join(build.topsrcdir, 'taskcluster', 'ci')
+    root = os.path.join(root, 'taskcluster', 'ci')
     tg = getattr(TaskGraphGenerator(root_dir=root, parameters=params), attr)
     labels = [label for label in tg.graph.visit_postorder()]
 
     os.chdir(cwd)
 
     with open(cache, 'w') as fh:
         fh.write('\n'.join(labels))
     return labels