diff --git a/src/add-ons/disk_systems/bfs/BFSAddOn.cpp b/src/add-ons/disk_systems/bfs/BFSAddOn.cpp
index 274f148395..41b8d3e9ee 100644
--- a/src/add-ons/disk_systems/bfs/BFSAddOn.cpp
+++ b/src/add-ons/disk_systems/bfs/BFSAddOn.cpp
@@ -103,8 +103,7 @@ BFSAddOn::CreatePartitionHandle(BMutablePartition* partition,
 bool
 BFSAddOn::CanInitialize(const BMutablePartition* partition)
 {
-	// TODO: Check partition size.
-	return true;
+	return partition->Size() >= 1L * 1024 * 1024;
 }
 
 
@@ -130,6 +129,19 @@ BFSAddOn::ValidateInitialize(const BMutablePartition* partition, BString* name,
 	if (error != B_OK)
 		return error;
 
+	off_t size = partition->Size();
+	uint32 blockSize = parameters.blockSize;
+	if (size < 2 * 1024 * 1024) {
+		if (blockSize != 1024)
+			return B_BAD_VALUE;
+	} else if (size < 4 * 1024 * 1024) {
+		if (blockSize >= 4 * 1024)
+			return B_BAD_VALUE;
+	} else if (size < 8 * 1024 * 1024) {
+		if (blockSize >= 8 * 1024)
+			return B_BAD_VALUE;
+	}
+
 	return B_OK;
 }
 
diff --git a/src/add-ons/disk_systems/bfs/InitializeParameterEditor.cpp b/src/add-ons/disk_systems/bfs/InitializeParameterEditor.cpp
index 621d15f818..7eacc25103 100644
--- a/src/add-ons/disk_systems/bfs/InitializeParameterEditor.cpp
+++ b/src/add-ons/disk_systems/bfs/InitializeParameterEditor.cpp
@@ -59,6 +59,16 @@ InitializeBFSEditor::SetTo(BPartition* partition)
 		name = partition->ContentName();
 	if (!name.IsEmpty())
 		fNameControl->SetText(name.String());
+	off_t size = partition->Size();
+	if (size < 2 * 1024 * 1024) {
+		f1KBlockMenuItem->SetMarked(true);
+		f2KBlockMenuItem->SetEnabled(false);
+	} else {
+		f2KBlockMenuItem->SetEnabled(true);
+		f2KBlockMenuItem->SetMarked(true);
+	}
+	f4KBlockMenuItem->SetEnabled(size >= 4 * 1024 * 1024);
+	f8KBlockMenuItem->SetEnabled(size >= 8 * 1024 * 1024);
 }
 
 
@@ -117,24 +127,26 @@ InitializeBFSEditor::_CreateViewControls()
 	BPopUpMenu* blocksizeMenu = new BPopUpMenu("blocksize");
 	BMessage* message = new BMessage(MSG_BLOCK_SIZE);
 	message->AddString("size", "1024");
-	blocksizeMenu->AddItem(new BMenuItem(
-		B_TRANSLATE("1024 (Mostly small files)"), message));
+	f1KBlockMenuItem = new BMenuItem(B_TRANSLATE("1024 (Mostly small files)"), message);
+	blocksizeMenu->AddItem(f1KBlockMenuItem);
+
 	message = new BMessage(MSG_BLOCK_SIZE);
 	message->AddString("size", "2048");
-	BMenuItem* defaultItem = new BMenuItem(B_TRANSLATE("2048 (Recommended)"),
+	f2KBlockMenuItem = new BMenuItem(B_TRANSLATE("2048 (Recommended)"),
 		message);
-	blocksizeMenu->AddItem(defaultItem);
+	blocksizeMenu->AddItem(f2KBlockMenuItem);
 	message = new BMessage(MSG_BLOCK_SIZE);
 	message->AddString("size", "4096");
-	blocksizeMenu->AddItem(new BMenuItem("4096", message));
+	f4KBlockMenuItem = new BMenuItem("4096", message);
+	blocksizeMenu->AddItem(f4KBlockMenuItem);
 	message = new BMessage(MSG_BLOCK_SIZE);
 	message->AddString("size", "8192");
-	blocksizeMenu->AddItem(new BMenuItem(
-		B_TRANSLATE("8192 (Mostly large files)"), message));
+	f8KBlockMenuItem = new BMenuItem(
+		B_TRANSLATE("8192 (Mostly large files)"), message);
+	blocksizeMenu->AddItem(f8KBlockMenuItem);
 
 	fBlockSizeMenuField = new BMenuField(B_TRANSLATE("Blocksize:"),
 		blocksizeMenu);
-	defaultItem->SetMarked(true);
 
 	fUseIndicesCheckBox = new BCheckBox(B_TRANSLATE("Enable query support"),
 		NULL);
diff --git a/src/add-ons/disk_systems/bfs/InitializeParameterEditor.h b/src/add-ons/disk_systems/bfs/InitializeParameterEditor.h
index 9f7abc32e9..43e8139ba0 100644
--- a/src/add-ons/disk_systems/bfs/InitializeParameterEditor.h
+++ b/src/add-ons/disk_systems/bfs/InitializeParameterEditor.h
@@ -14,6 +14,7 @@
 
 class BCheckBox;
 class BMenuField;
+class BMenuItem;
 class BTextControl;
 class BView;
 
@@ -41,6 +42,10 @@ private:
 				BTextControl*	fNameControl;
 				BMenuField*		fBlockSizeMenuField;
 				BCheckBox*		fUseIndicesCheckBox;
+				BMenuItem*		f1KBlockMenuItem;
+				BMenuItem*		f2KBlockMenuItem;
+				BMenuItem*		f4KBlockMenuItem;
+				BMenuItem*		f8KBlockMenuItem;
 };