Index: src/OFINICategory.m
==================================================================
--- src/OFINICategory.m
+++ src/OFINICategory.m
@@ -20,12 +20,13 @@
 #include "config.h"
 
 #import "OFINICategory.h"
 #import "OFINICategory+Private.h"
 #import "OFArray.h"
-#import "OFString.h"
+#import "OFCharacterSet.h"
 #import "OFStream.h"
+#import "OFString.h"
 
 #import "OFInvalidArgumentException.h"
 #import "OFInvalidFormatException.h"
 
 @interface OFINICategoryPair: OFObject
@@ -40,20 +41,21 @@
 @public
 	OFString *_comment;
 }
 @end
 
+static OFCharacterSet *needsEscapeCharacterSet;
+
 static OFString *
 escapeString(OFString *string)
 {
 	OFMutableString *mutableString;
 
-	/* FIXME: Optimize */
-	if (![string hasPrefix: @" "] && ![string hasPrefix: @"\t"] &&
-	    ![string hasPrefix: @"\f"] && ![string hasSuffix: @" "] &&
-	    ![string hasSuffix: @"\t"] && ![string hasSuffix: @"\f"] &&
-	    ![string containsString: @"\""] && ![string containsString: @"="])
+	if (![string hasPrefix: @" "] && ![string hasSuffix: @" "] &&
+	    ![string hasPrefix: @"\t"] && ![string hasSuffix: @"\t"] &&
+	    [string indexOfCharacterFromSet: needsEscapeCharacterSet] ==
+	    OFNotFound)
 		return string;
 
 	mutableString = [[string mutableCopy] autorelease];
 
 	[mutableString replaceOccurrencesOfString: @"\\" withString: @"\\\\"];
@@ -99,10 +101,19 @@
 }
 @end
 
 @implementation OFINICategory
 @synthesize name = _name;
+
++ (void)initialize
+{
+	if (self != [OFINICategory class])
+		return;
+
+	needsEscapeCharacterSet = [[OFCharacterSet alloc]
+	    initWithCharactersInString: @"\r\n\f\"\\="];
+}
 
 - (instancetype)of_initWithName: (OFString *)name OF_DIRECT
 {
 	self = [super init];
 

Index: tests/OFINIFileTests.m
==================================================================
--- tests/OFINIFileTests.m
+++ tests/OFINIFileTests.m
@@ -122,13 +122,13 @@
 	    @"\r\n"
 	    @"[foobar]\r\n"
 	    @"#foobarcomment\r\n"
 	    @"qux=\" asd\"\r\n"
 	    @"quxquxqux=\"hello\\\"wörld\"\r\n"
-	    @"qux2=\"a\\f\"\r\n"
+	    @"qux2=\"a\\n\"\r\n"
 	    @"\"asd=asd\"=foobar\r\n"
-	    @"qux3=a\fb\r\n"
+	    @"qux3=\"a\\fb\"\r\n"
 	    @"\r\n"
 	    @"[types]\r\n"
 	    @"integer=16\r\n"
 	    @"bool=false\r\n"
 	    @"float=0.25\r\n"

Index: tests/testfile.ini
==================================================================
--- tests/testfile.ini
+++ tests/testfile.ini
@@ -9,11 +9,11 @@
 [foobar]
 #foobarcomment
 qux=" asd"
 "quxqux " = asd
 quxquxqux="hello\"wörld"
-qux2="a\f"
+qux2="a\n"
 "asd=asd"=foobar
 
 [types]
 integer = 0x20
 bool = true