Excel crashes after running solver

I have a routine that calls a solver function on each iteration. The results is Ok but after am done running my model, if I try to edit a cell using F2 excel crashes. Can someone tell me what the problem is? Thanks.

Public Sub NPV

Application.ScreenUpdating = False
Worksheets(strSHEETNAME_PricingModel).Activate
SolverOk SetCell:=Worksheets(strSHEETNAME_PricingModel).Range("NPV").Value, MaxMinVal:=3, ValueOf:="0", _
ByChange:=Worksheets("PricingModel").Range(BreakevenSpread).Value
SolverSolve UserFinish:=True

End Sub