diff --git a/lldb/test/API/commands/register/register/aarch64_sve_registers/rw_access_dynamic_resize/TestSVEThreadedDynamic.py b/lldb/test/API/commands/register/register/aarch64_sve_registers/rw_access_dynamic_resize/TestSVEThreadedDynamic.py
--- a/lldb/test/API/commands/register/register/aarch64_sve_registers/rw_access_dynamic_resize/TestSVEThreadedDynamic.py
+++ b/lldb/test/API/commands/register/register/aarch64_sve_registers/rw_access_dynamic_resize/TestSVEThreadedDynamic.py
@@ -125,8 +125,6 @@
 
         process = self.dbg.GetSelectedTarget().GetProcess()
 
-        thread1 = process.GetThreadAtIndex(0)
-
         self.expect(
             "thread info 1",
             STOPPED_DUE_TO_BREAKPOINT,
@@ -140,6 +138,10 @@
 
         self.runCmd("process continue", RUN_SUCCEEDED)
 
+        # If we start the checks too quickly, thread 3 may not have started.
+        while (process.GetNumThreads() < 3):
+            pass
+
         for idx in range(1, process.GetNumThreads()):
             thread = process.GetThreadAtIndex(idx)
             if thread.GetStopReason() != lldb.eStopReasonBreakpoint: