[checkcheckta]

I live in an apartment with up-lower sliding window, recently the lower panel cannot hold when lifted, it slides down immediately. Can someone please tell me how to fix it?

 

[Ron6519]

I live in an apartment with up-lower sliding window, recently the lower panel cannot hold when lifted, it slides down immediately. Can someone please tell me how to fix it?

There are balances on the side of the window that counter balances the windows weight as it is raised. It sounds like one is either broken or not engaged. Has someone tilted the window in recently to clean it? If so, the balance might have disengaged.
If it's broken, call the super and have him replace the broken balance.
Or call the window company direct and have them either send you a repacement or repair it under warranty (if it exists)
Ron