diff --git a/src/preferences/filetypes/ApplicationTypeWindow.cpp b/src/preferences/filetypes/ApplicationTypeWindow.cpp
index 1980970635..ada2417bc6 100644
--- a/src/preferences/filetypes/ApplicationTypeWindow.cpp
+++ b/src/preferences/filetypes/ApplicationTypeWindow.cpp
@@ -133,7 +133,7 @@ ApplicationTypeWindow::ApplicationTypeWindow(BPoint position, const BEntry& entr
 	// filter out invalid characters that can't be part of a MIME type name
 	BTextView* textView = fSignatureControl->TextView();
 	textView->SetMaxBytes(B_MIME_TYPE_LENGTH);
-	const char* disallowedCharacters = "/<>@,;:\"()[]?=";
+	const char* disallowedCharacters = "<>@,;:\"()[]?=";
 	for (int32 i = 0; disallowedCharacters[i]; i++) {
 		textView->DisallowChar(disallowedCharacters[i]);
 	}
diff --git a/src/preferences/filetypes/FileTypeWindow.cpp b/src/preferences/filetypes/FileTypeWindow.cpp
index fc25be7608..74627480cd 100644
--- a/src/preferences/filetypes/FileTypeWindow.cpp
+++ b/src/preferences/filetypes/FileTypeWindow.cpp
@@ -71,7 +71,7 @@ FileTypeWindow::FileTypeWindow(BPoint position, const BMessage& refs)
 
 	// filter out invalid characters that can't be part of a MIME type name
 	BTextView* textView = fTypeControl->TextView();
-	const char* disallowedCharacters = "/<>@,;:\"()[]?=";
+	const char* disallowedCharacters = "<>@,;:\"()[]?=";
 	for (int32 i = 0; disallowedCharacters[i]; i++) {
 		textView->DisallowChar(disallowedCharacters[i]);
 	}