diff --git a/tfexec/internal/e2etest/show_test.go b/tfexec/internal/e2etest/show_test.go
index 4268fe74..115438de 100644
--- a/tfexec/internal/e2etest/show_test.go
+++ b/tfexec/internal/e2etest/show_test.go
@@ -192,12 +192,10 @@ func TestShowStateFile013(t *testing.T) {
 
 // Plan files cannot be transferred between different Terraform versions,
 // so we maintain one fixture per supported version
-func TestShowPlanFile012(t *testing.T) {
+func TestShowPlanFile012_linux(t *testing.T) {
 	runTestVersions(t, []string{testutil.Latest012}, "non_default_planfile_012", func(t *testing.T, tfv *version.Version, tf *tfexec.Terraform) {
-		// plan file fixture was created in Linux, and is
-		// not compatible with Windows
-		if runtime.GOOS == "windows" {
-			t.Skip("plan file created in 0.12 on Linux is not compatible with Windows")
+		if runtime.GOOS != "linux" {
+			t.Skip("plan file created in 0.12 on Linux is not compatible with other systems")
 		}
 
 		providerName := "null"
@@ -322,12 +320,10 @@ func TestShowPlanFile013(t *testing.T) {
 	})
 }
 
-func TestShowPlanFileRaw012(t *testing.T) {
+func TestShowPlanFileRaw012_linux(t *testing.T) {
 	runTestVersions(t, []string{testutil.Latest012}, "non_default_planfile_012", func(t *testing.T, tfv *version.Version, tf *tfexec.Terraform) {
-		// plan file fixture was created in Linux, and is
-		// not compatible with Windows
-		if runtime.GOOS == "windows" {
-			t.Skip("plan file created in 0.12 on Linux is not compatible with Windows")
+		if runtime.GOOS != "linux" {
+			t.Skip("plan file created in 0.12 on Linux is not compatible with other systems")
 		}
 
 		// crlf will standardize our line endings for us
diff --git a/tfinstall/git_ref.go b/tfinstall/git_ref.go
index 60c01783..71149bd4 100644
--- a/tfinstall/git_ref.go
+++ b/tfinstall/git_ref.go
@@ -5,7 +5,9 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
+	"os"
 	"os/exec"
+	"path/filepath"
 	"runtime"
 
 	"github.com/go-git/go-git/v5"
@@ -72,7 +74,14 @@ func (opt *GitRefOption) ExecPath(ctx context.Context) (string, error) {
 		binFile.Close()
 	}
 
-	cmd := exec.CommandContext(ctx, "go", "build", "-mod", "vendor", "-o", binName)
+	goArgs := []string{"build", "-o", binName}
+
+	vendorDir := filepath.Join(installDir, "vendor")
+	if fi, err := os.Stat(vendorDir); err == nil && fi.IsDir() {
+		goArgs = append(goArgs, "-mod", "vendor")
+	}
+
+	cmd := exec.CommandContext(ctx, "go", goArgs...)
 	cmd.Dir = installDir
 	out, err := cmd.CombinedOutput()
 	log.Print(string(out))