Index: src/OFINICategory+Private.h
==================================================================
--- src/OFINICategory+Private.h
+++ src/OFINICategory+Private.h
@@ -24,11 +24,12 @@
 
 @class OFStream;
 
 OF_DIRECT_MEMBERS
 @interface OFINICategory ()
-- (instancetype)of_initWithName: (OFString *)name OF_METHOD_FAMILY(init);
+- (instancetype)of_initWithName: (nullable OFString *)name
+    OF_METHOD_FAMILY(init);
 - (void)of_parseLine: (OFString *)line;
 - (bool)of_writeToStream: (OFStream *)stream
 		encoding: (OFStringEncoding)encoding
 		   first: (bool)first;
 @end

Index: src/OFINICategory.m
==================================================================
--- src/OFINICategory.m
+++ src/OFINICategory.m
@@ -153,15 +153,19 @@
 }
 
 - (void)of_parseLine: (OFString *)line
 {
 	if (![line hasPrefix: @";"]) {
-		OFINICategoryPair *pair =
-		    [[[OFINICategoryPair alloc] init] autorelease];
+		OFINICategoryPair *pair;
 		OFString *key, *value;
 		size_t pos;
 
+		if (_name == nil)
+			@throw [OFInvalidFormatException exception];
+
+		pair = [[[OFINICategoryPair alloc] init] autorelease];
+
 		if ((pos = [line rangeOfString: @"="].location) == OFNotFound)
 			@throw [OFInvalidFormatException exception];
 
 		key = unescapeString([line substringToIndex: pos]
 		    .stringByDeletingEnclosingWhitespaces);
@@ -477,14 +481,16 @@
 		   first: (bool)first
 {
 	if (_lines.count == 0)
 		return false;
 
-	if (first)
-		[stream writeFormat: @"[%@]\r\n", _name];
-	else
-		[stream writeFormat: @"\r\n[%@]\r\n", _name];
+	if (_name != nil) {
+		if (first)
+			[stream writeFormat: @"[%@]\r\n", _name];
+		else
+			[stream writeFormat: @"\r\n[%@]\r\n", _name];
+	}
 
 	for (id line in _lines) {
 		if ([line isKindOfClass: [OFINICategoryComment class]]) {
 			OFINICategoryComment *comment = line;
 			[stream writeFormat: @"%@\r\n", comment->_comment];

Index: src/OFINIFile.h
==================================================================
--- src/OFINIFile.h
+++ src/OFINIFile.h
@@ -32,10 +32,11 @@
  * @brief A class for reading, creating and modifying INI files.
  */
 OF_SUBCLASSING_RESTRICTED
 @interface OFINIFile: OFObject
 {
+	OFINICategory *_prologue;
 	OFMutableArray OF_GENERIC(OFINICategory *) *_categories;
 }
 
 /**
  * @brief All categories in the INI file.

Index: src/OFINIFile.m
==================================================================
--- src/OFINIFile.m
+++ src/OFINIFile.m
@@ -77,10 +77,11 @@
 - (instancetype)initWithIRI: (OFIRI *)IRI encoding: (OFStringEncoding)encoding
 {
 	self = [super init];
 
 	@try {
+		_prologue = [[OFINICategory alloc] of_initWithName: nil];
 		_categories = [[OFMutableArray alloc] init];
 
 		[self of_parseIRI: IRI encoding: encoding];
 	} @catch (id e) {
 		[self release];
@@ -90,10 +91,11 @@
 	return self;
 }
 
 - (void)dealloc
 {
+	[_prologue release];
 	[_categories release];
 
 	[super dealloc];
 }
 
@@ -116,11 +118,11 @@
 
 - (void)of_parseIRI: (OFIRI *)IRI encoding: (OFStringEncoding)encoding
 {
 	void *pool = objc_autoreleasePoolPush();
 	OFStream *file;
-	OFINICategory *category = nil;
+	OFINICategory *category = _prologue;
 	OFString *line;
 
 	if (encoding == OFStringEncodingAutodetect)
 		encoding = OFStringEncodingUTF8;
 
@@ -147,16 +149,12 @@
 			categoryName = [line substringWithRange:
 			    OFMakeRange(1, line.length - 2)];
 			category = [[[OFINICategory alloc]
 			    of_initWithName: categoryName] autorelease];
 			[_categories addObject: category];
-		} else {
-			if (category == nil)
-				@throw [OFInvalidFormatException exception];
-
+		} else
 			[category of_parseLine: line];
-		}
 	}
 
 	objc_autoreleasePoolPop(pool);
 }
 
@@ -168,10 +166,13 @@
 - (void)writeToIRI: (OFIRI *)IRI encoding: (OFStringEncoding)encoding
 {
 	void *pool = objc_autoreleasePoolPush();
 	OFStream *file = [OFIRIHandler openItemAtIRI: IRI mode: @"w"];
 	bool first = true;
+
+	if ([_prologue of_writeToStream: file encoding: encoding first: true])
+		first = false;
 
 	for (OFINICategory *category in _categories)
 		if ([category of_writeToStream: file
 				      encoding: encoding
 					 first: first])

Index: tests/OFINIFileTests.m
==================================================================
--- tests/OFINIFileTests.m
+++ tests/OFINIFileTests.m
@@ -19,10 +19,12 @@
 
 #include "config.h"
 
 #import "ObjFW.h"
 #import "ObjFWTest.h"
+
+#import "OFEmbeddedIRIHandler.h"
 
 @interface OFINIFileTests: OTTestCase
 {
 	OFINIFile *_file;
 }
@@ -107,11 +109,13 @@
 	    [OFArray array]);
 }
 
 - (void)testWriteToIRIEncoding
 {
-	OFString *expectedOutput = @"[tests]\r\n"
+	OFString *expectedOutput = @"; Comment before categories\r\n"
+	    @"\r\n"
+	    @"[tests]\r\n"
 	    @"foo=baz\r\n"
 	    @"foobar=baz\r\n"
 	    @";comment\r\n"
 	    @"new=new\r\n"
 	    @"\r\n"
@@ -170,6 +174,17 @@
 	}
 #else
 	(void)expectedOutput;
 #endif
 }
+
+- (void)testValuePairOutsideOfCategoryRejected
+{
+	OFIRI *IRI = [OFIRI IRIWithString: @"embedded:testfile_broken.ini"];
+
+	OFRegisterEmbeddedFile(@"testfile_broken.ini",
+	    (const uint8_t *)"; comment\r\na=b", 14);
+
+	OTAssertThrowsSpecific([OFINIFile fileWithIRI: IRI],
+	    OFInvalidFormatException);
+}
 @end

Index: tests/testfile.ini
==================================================================
--- tests/testfile.ini
+++ tests/testfile.ini
@@ -1,5 +1,7 @@
+; Comment before categories
+
 [tests]
 foo = bar
 foobar=baz
 ;comment