diff --git a/pkg/message/parser.go b/pkg/message/parser.go
index fce95a81..f90fda79 100644
--- a/pkg/message/parser.go
+++ b/pkg/message/parser.go
@@ -197,6 +197,9 @@ func convertForeignEncodings(p *parser.Parser) error {
 
 	return p.NewWalker().
 		RegisterContentTypeHandler("text/html", func(p *parser.Part) error {
+			if p.IsAttachment() {
+				return nil
+			}
 			if err := p.ConvertToUTF8(); err != nil {
 				return err
 			}
@@ -313,24 +316,14 @@ func collectBodyParts(p *parser.Parser, preferredContentType string) (parser.Par
 			return bestChoice(childParts, preferredContentType), nil
 		}).
 		RegisterRule("text/plain", func(p *parser.Part, visit parser.Visit) (interface{}, error) {
-			disp, _, err := p.ContentDisposition()
-			if err != nil {
-				disp = ""
-			}
-
-			if disp == "attachment" {
+			if p.IsAttachment() {
 				return parser.Parts{}, nil
 			}
 
 			return parser.Parts{p}, nil
 		}).
 		RegisterRule("text/html", func(p *parser.Part, visit parser.Visit) (interface{}, error) {
-			disp, _, err := p.ContentDisposition()
-			if err != nil {
-				disp = ""
-			}
-
-			if disp == "attachment" {
+			if p.IsAttachment() {
 				return parser.Parts{}, nil
 			}
 
diff --git a/pkg/message/parser/handler.go b/pkg/message/parser/handler.go
index 4f719541..57873589 100644
--- a/pkg/message/parser/handler.go
+++ b/pkg/message/parser/handler.go
@@ -33,7 +33,7 @@ func (h *handler) matchPart(p *Part) bool {
 }
 
 func (h *handler) matchPartSkipAttachment(p *Part) bool {
-	return !p.isAttachment() && h.matchPart(p)
+	return !p.IsAttachment() && h.matchPart(p)
 }
 
 func (h *handler) matchType(p *Part) bool {
diff --git a/pkg/message/parser/part.go b/pkg/message/parser/part.go
index 7382a28c..8a259efc 100644
--- a/pkg/message/parser/part.go
+++ b/pkg/message/parser/part.go
@@ -209,7 +209,7 @@ func (p *Part) isMultipartMixedOrRelated() bool {
 	return t == "multipart/mixed" || t == "multipart/related"
 }
 
-func (p *Part) isAttachment() bool {
+func (p *Part) IsAttachment() bool {
 	disp, _, err := p.ContentDisposition()
 	if err != nil {
 		disp = ""
diff --git a/tests/features/smtp/send/plain_to_internal.feature b/tests/features/smtp/send/plain_to_internal.feature
index 72b3e66c..03feb069 100644
--- a/tests/features/smtp/send/plain_to_internal.feature
+++ b/tests/features/smtp/send/plain_to_internal.feature
@@ -184,9 +184,7 @@ Feature: SMTP sending of PLAIN messages to Internal recipient
       Content-Disposition: attachment; filename="index.html"
       Content-Transfer-Encoding: base64
 
-      IDwhRE9DVFlQRSBodG1sPg0KPGh0bWw+DQo8aGVhZD4NCjx0aXRsZT5QYWdlIFRpdGxlPC90
-      aXRsZT4NCjwvaGVhZD4NCjxib2R5Pg0KDQo8aDE+TXkgRmlyc3QgSGVhZGluZzwvaDE+DQo8
-      cD5NeSBmaXJzdCBwYXJhZ3JhcGguPC9wPg0KDQo8L2JvZHk+DQo8L2h0bWw+IA==
+      PCFET0NUWVBFIGh0bWw+
       --------------WI90RPIYF20K6dGXjs7dm2mi
       Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document;
         name="test.docx"
@@ -669,7 +667,7 @@ Feature: SMTP sending of PLAIN messages to Internal recipient
               "content-disposition": "attachment",
               "content-disposition-filename": "index.html",
               "transfer-encoding": "base64",
-              "body-is": "PCFET0NUWVBFIGh0bWw+PGh0bWw+PGhlYWQ+Cjx0aXRsZT5QYWdlIFRpdGxlPC90aXRsZT4KPC9o\r\nZWFkPgo8Ym9keT4KCjxoMT5NeSBGaXJzdCBIZWFkaW5nPC9oMT4KPHA+TXkgZmlyc3QgcGFyYWdy\r\nYXBoLjwvcD4KCgogPC9ib2R5PjwvaHRtbD4="
+              "body-is": "PCFET0NUWVBFIGh0bWw+"
             },
             {
               "content-type": "application/vnd.openxmlformats-officedocument.wordprocessingml.document",