diff --git a/src/machine.cpp b/src/machine.cpp
index 48c5ca6cb7..510745ffdd 100644
--- a/src/machine.cpp
+++ b/src/machine.cpp
@@ -75,7 +75,7 @@ dispose(Thread* t, Thread* o, bool remove)
     // end debug
 
     if (o->parent) {
-      Thread* previous;
+      Thread* previous = 0;
       for (Thread* p = o->parent->child; p;) {
         if (p == o) {
           if (p == o->parent->child) {
diff --git a/src/posix.cpp b/src/posix.cpp
index 1f6a102b34..62d03c83a7 100644
--- a/src/posix.cpp
+++ b/src/posix.cpp
@@ -157,7 +157,7 @@ class MySystem: public System {
     }
 
     void remove(Thread* t) {
-      Thread* previous;
+      Thread* previous = 0;
       for (Thread* current = first; current;) {
         if (t == current) {
           if (current == first) {
diff --git a/src/windows.cpp b/src/windows.cpp
index f5033417eb..c06cf27f7d 100644
--- a/src/windows.cpp
+++ b/src/windows.cpp
@@ -158,7 +158,7 @@ class MySystem: public System {
     }
 
     void remove(Thread* t) {
-      Thread* previous;
+      Thread* previous = 0;
       for (Thread* current = first; current;) {
         if (t == current) {
           if (current == first) {