diff --git a/src/cmd/go/internal/clean/clean.go b/src/cmd/go/internal/clean/clean.go
index 5f4bf4e6c8e..69e17482b44 100644
--- a/src/cmd/go/internal/clean/clean.go
+++ b/src/cmd/go/internal/clean/clean.go
@@ -178,7 +178,9 @@ func runClean(cmd *base.Command, args []string) {
 				}
 			}
 			if err != nil {
-				base.Errorf("go clean -testcache: %v", err)
+				if _, statErr := os.Stat(dir); !os.IsNotExist(statErr) {
+					base.Errorf("go clean -testcache: %v", err)
+				}
 			}
 		}
 	}
diff --git a/src/cmd/go/testdata/script/clean_testcache.txt b/src/cmd/go/testdata/script/clean_testcache.txt
index dd7846462e1..b3f32fe696a 100644
--- a/src/cmd/go/testdata/script/clean_testcache.txt
+++ b/src/cmd/go/testdata/script/clean_testcache.txt
@@ -9,6 +9,13 @@ go clean -testcache
 go test x_test.go
 ! stdout 'cached'
 
+# golang.org/issue/29100: 'go clean -testcache' should succeed
+# if the cache directory doesn't exist at all.
+# It should not write a testexpire.txt file, since there are no
+# test results that need to be invalidated in the first place.
+env GOCACHE=$WORK/nonexistent
+go clean -testcache
+! exists $WORK/nonexistent
 
 -- x/x_test.go --
 package x_test
@@ -16,4 +23,4 @@ import (
     "testing"
 )
 func TestMain(t *testing.T) {
-}
\ No newline at end of file
+}