Can not enable maintenance mode

[Petter B]

I cannot enable maintenance mode. When I enable it and click Save, the box just gets unchecked again.
Same thing with the option Comressed output on the same page.
In the file Settings.php $maintenance = 1;
but forum still works as usual..?

[Shambles]

In the file Settings.php $maintenance = 1;

Does $maintenance = 0; occur later in your Settings.php file?

[Petter B]

Does $maintenance = 0; occur later in your Settings.php file?

Yes! 
At line 69, shall I delete it?

Could it be a similar problem with not being able to select Compressed output?

[Sir Osis of Liver]

There shouldn't be a line 69 in Settings.php.  You should replace it with a clean file, manually add database credentials, then run repair_settings.php.

[Petter B]

OK. Where can I get a clean settings.php ?

[Shambles]

Does $maintenance = 0; occur later in your Settings.php file?

Yes! 
At line 69, shall I delete it?

Could it be a similar problem with not being able to select Compressed output?

I would say Yes and Yes, though there may be other duplicated entries in your file, so go with Cirrhosis's suggestion and get a clean Settings.php from the installation package.

You're welcome.

[Sir Osis of Liver]

Attached.