it is strip mall....Hmm, ok. I haven't been able to recreate the bug. Does is say "Strip Mall" or "Destroyed Mall"? The Strip Mall has a yellow circle in the center of the map. The Destroyed Mall has a red circle on the left side of the map.
If you're sure you've explore both:
1) Hit "Shift+'O'" to open the command console
2) Paste the following and hit enter: cs_destroyed_mall.explored=1
3) Paste the following and hit enter: cs_strip_mall.explored=1
This should resolve the issue and let you start Act 2.
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and console doesnt helped.... (ok helped, i copyed it bad) thx