If you have a 2009-2013 Toyota Corolla and you find that the trunk won't shut or latch, then you will want to check the weatherstrip around the trunk and make sure it hasn't come out of place. In some places you may see that the strip is deformed... If you reposition the weatherstrip back into place and make sure that the outer edges are tucked back into the trim, it will start closing without replacing the seal. This pic shows the upper edge being tucked back under the trim. Here is a pic of the bottom edge being tucked back into place... Also if you look around the rear taillight assemblies, this is what the seal looks like tucked in...
