diff --git a/src/V3Error.cpp b/src/V3Error.cpp
index c70b8dc95..97852cc73 100644
--- a/src/V3Error.cpp
+++ b/src/V3Error.cpp
@@ -482,7 +482,7 @@ void V3Error::v3errorEnd (ostringstream& sstr) {
 		}
 #ifndef _V3ERROR_NO_GLOBAL_
 		if (debug()) {
-		    v3Global.rootp()->dumpTreeFile(v3Global.debugFilename("final.tree",99));
+		    v3Global.rootp()->dumpTreeFile(v3Global.debugFilename("final.tree",999));
 		    V3Stats::statsFinalAll(v3Global.rootp());
 		    V3Stats::statsReport();
 		}
diff --git a/src/V3Global.h b/src/V3Global.h
index a03f6013e..fede611d3 100644
--- a/src/V3Global.h
+++ b/src/V3Global.h
@@ -80,7 +80,7 @@ public:
     string debugFilename(const string& nameComment, int newNumber=0) {
 	++m_debugFileNumber;
 	if (newNumber) m_debugFileNumber = newNumber;
-	char digits[100]; sprintf(digits, "%02d", m_debugFileNumber);
+	char digits[100]; sprintf(digits, "%03d", m_debugFileNumber);
 	return opt.makeDir()+"/"+opt.prefix()+"_"+digits+"_"+nameComment;
     }
     bool needHInlines() const { return m_needHInlines; }
diff --git a/src/Verilator.cpp b/src/Verilator.cpp
index b84e090de..e8da2f6d9 100644
--- a/src/Verilator.cpp
+++ b/src/Verilator.cpp
@@ -677,7 +677,7 @@ int main(int argc, char** argv, char** env) {
     }
 
     // Final steps
-    V3Global::dumpGlobalTree("final.tree",99);
+    V3Global::dumpGlobalTree("final.tree",999);
     V3Error::abortIfWarnings();
 
     if (!v3Global.opt.lintOnly() && !v3Global.opt.cdc()