diff --git a/src/sentry_sync.h b/src/sentry_sync.h
index 62028777d..66309886a 100644
--- a/src/sentry_sync.h
+++ b/src/sentry_sync.h
@@ -99,9 +99,9 @@ SleepConditionVariableCS_PREVISTA(
 {
     DWORD result = 0;
 
+    InterlockedIncrement((LONG *)&cv->Waiters);
     LeaveCriticalSection(cs);
 
-    InterlockedIncrement((LONG *)&cv->Waiters);
     result = WaitForSingleObject(cv->Semaphore, timeout);
 
     // send event only on target
@@ -122,12 +122,14 @@ WakeConditionVariable_PREVISTA(PCONDITION_VARIABLE_PREVISTA ConditionVariable)
         return;
     }
 
-    if (ConditionVariable->Waiters == 0) {
+    const LONG waiters = InterlockedCompareExchange(
+        (volatile LONG *)&ConditionVariable->Waiters, 0, 0);
+    if (waiters == 0) {
         return;
     }
 
     // set target for continue event, alert it on first occurance
-    ConditionVariable->Target = ConditionVariable->Waiters - 1;
+    ConditionVariable->Target = waiters - 1;
 
     SignalObjectAndWait(ConditionVariable->Semaphore,
         ConditionVariable->ContinueEvent, INFINITE, FALSE);