diff --git a/gopls/internal/regtest/misc/vendor_test.go b/gopls/internal/regtest/misc/vendor_test.go
index 0e615f2818..324a8006fa 100644
--- a/gopls/internal/regtest/misc/vendor_test.go
+++ b/gopls/internal/regtest/misc/vendor_test.go
@@ -5,7 +5,6 @@
 package misc
 
 import (
-	"runtime"
 	"testing"
 
 	. "golang.org/x/tools/internal/lsp/regtest"
@@ -27,9 +26,16 @@ var Goodbye error
 
 func TestInconsistentVendoring(t *testing.T) {
 	testenv.NeedsGo1Point(t, 14)
-	if runtime.GOOS == "windows" {
-		t.Skipf("skipping test due to flakiness on Windows: https://golang.org/issue/49646")
-	}
+
+	// TODO(golang/go#49646): delete this comment once this test is stable.
+	//
+	// In golang/go#49646, this test is reported as flaky on Windows. We believe
+	// this is due to file contention from go mod vendor that should be resolved.
+	// If this test proves to still be flaky, skip it.
+	//
+	// if runtime.GOOS == "windows" {
+	// 	t.Skipf("skipping test due to flakiness on Windows: https://golang.org/issue/49646")
+	// }
 
 	const pkgThatUsesVendoring = `
 -- go.mod --
diff --git a/internal/lsp/command.go b/internal/lsp/command.go
index ae19a7da05..072ee08e80 100644
--- a/internal/lsp/command.go
+++ b/internal/lsp/command.go
@@ -256,11 +256,19 @@ func (c *commandHandler) Vendor(ctx context.Context, args command.URIArg) error
 		progress:    "Running go mod vendor",
 		forURI:      args.URI,
 	}, func(ctx context.Context, deps commandDeps) error {
-		_, err := deps.snapshot.RunGoCommandDirect(ctx, source.Normal|source.AllowNetwork, &gocommand.Invocation{
+		// Use RunGoCommandPiped here so that we don't compete with any other go
+		// command invocations. go mod vendor deletes modules.txt before recreating
+		// it, and therefore can run into file locking issues on Windows if that
+		// file is in use by another process, such as go list.
+		//
+		// If golang/go#44119 is resolved, go mod vendor will instead modify
+		// modules.txt in-place. In that case we could theoretically allow this
+		// command to run concurrently.
+		err := deps.snapshot.RunGoCommandPiped(ctx, source.Normal|source.AllowNetwork, &gocommand.Invocation{
 			Verb:       "mod",
 			Args:       []string{"vendor"},
 			WorkingDir: filepath.Dir(args.URI.SpanURI().Filename()),
-		})
+		}, &bytes.Buffer{}, &bytes.Buffer{})
 		return err
 	})
 }
diff --git a/internal/lsp/source/view.go b/internal/lsp/source/view.go
index d263c1a9bf..f698a07e3e 100644
--- a/internal/lsp/source/view.go
+++ b/internal/lsp/source/view.go
@@ -98,6 +98,10 @@ type Snapshot interface {
 
 	// RunGoCommandPiped runs the given `go` command, writing its output
 	// to stdout and stderr. Verb, Args, and WorkingDir must be specified.
+	//
+	// RunGoCommandPiped runs the command serially using gocommand.RunPiped,
+	// enforcing that this command executes exclusively to other commands on the
+	// server.
 	RunGoCommandPiped(ctx context.Context, mode InvocationFlags, inv *gocommand.Invocation, stdout, stderr io.Writer) error
 
 	// RunGoCommandDirect runs the given `go` command. Verb, Args, and