diff --git a/mlir/lib/IR/Verifier.cpp b/mlir/lib/IR/Verifier.cpp
--- a/mlir/lib/IR/Verifier.cpp
+++ b/mlir/lib/IR/Verifier.cpp
@@ -44,7 +44,9 @@
 class OperationVerifier {
 public:
   explicit OperationVerifier(MLIRContext *context)
-      : parallelismEnabled(context->isMultithreadingEnabled()) {}
+      // TODO: Re-enable parallelism once deadlocks found in D104207 are
+      // resolved.
+      : parallelismEnabled(false) {}
 
   /// Verify the given operation.
   LogicalResult verifyOpAndDominance(Operation &op);