diff --git a/bitbake/lib/bb/server/process.py b/bitbake/lib/bb/server/process.py
index 8d12f00bd4..916ee0a0e5 100644
--- a/bitbake/lib/bb/server/process.py
+++ b/bitbake/lib/bb/server/process.py
@@ -375,7 +375,7 @@ class ProcessServer():
                 lock = bb.utils.lockfile(lockfile, shared=False, retry=False, block=False)
                 if not lock:
                     newlockcontents = get_lock_contents(lockfile)
-                    if not newlockcontents.startswith([os.getpid() + "\n", os.getpid() + " "]):
+                    if not newlockcontents[0].startswith([os.getpid() + "\n", os.getpid() + " "]):
                         # A new server was started, the lockfile contents changed, we can exit
                         serverlog("Lockfile now contains different contents, exiting: " + str(newlockcontents))
                         return