--- a/commands/msgview/open.go
+++ b/commands/msgview/open.go
@@ -5,6 +5,7 @@
 	"io"
 	"mime"
 	"os"
+	"path"
 	"path/filepath"
 
 	"git.sr.ht/~rjarry/aerc/app"
@@ -56,9 +57,9 @@
 			app.PushError(err.Error())
 			return
 		}
-		filename := part.FileName()
+		filename := path.Base(part.FileName())
 		var tmpFile *os.File
-		if filename == "" {
+		if filename == "." {
 			extension := ""
 			if exts, _ := mime.ExtensionsByType(mimeType); len(exts) > 0 {
 				extension = exts[0]