Who is responsible if a window falls from my condo unit?

Usually you, the unit owner. Under the Building Control Act, the person responsible for a window that is part of a flat is the flat's owner or whoever ordinarily has daily charge of its maintenance and use. The Building (Strata Management) Act also treats openable windows on a unit's exterior wall (casement, sliding, louvre or any window with moving parts) as part of the lot, not common property. Fixed windows are generally common property, maintained by the MCST, unless the strata title plan says otherwise. Check your strata title plan and by-laws for the windows in your unit.