A side lift spreader (1) for handling empty containers (6), and a method for adjusting a main frame (10) of an inverted side lift spreader. The inverted side lift spreader (1) comprises a main carriage (8) which is connectable to a lifting device (2) to be movable along a front side (39) of a mast (4) of the lifting device (2), the main frame (10) being carried by and sideways movable with respect to the main carriage (8), and main frame guiding means (27) for guiding a movement of the main frame (10) with respect to the main carriage (8). The main frame guiding means (27) comprises at least two links (30, 31, 32, 33), one first portion (52, 56, 60, 64) of each link (30, 31, 32, 33) being connected to the main frame (10) and one second portion (54, 58, 62, 66) of each link (30, 31, 32, 33) being connected to the main carriage (8). The second portions (54, 58, 62, 66) of the links (30, 31, 32, 33) are arranged at the main carriage (8) at respective points of attachment (76, 78, 80, 82) which are located, in use of the spreader (1), at an opposite side (84) of the mast (4) compared to the front side (39).