If you are in the process of doing a loan modification and you do not pay your mortgage, can the bank start foreclosure?

The answer really depends on what your mortgage says, but, typically, if you miss a monthly payment, and then don't "cure" the default (by making the payment) within another month, the bank is going to have the right to demand the entire balance of the note and foreclose.

Banks don't tyically move that quickly, and it might be 6 months or more after a default before they foreclose. But they can move quickly if they want to.
The fact that you may be negotiating with them doesn't prevent them from foreclosing. It may given them an incentive to delay a foreclosure, but they aren't obligated to delay

no, I just went through the same thing didnt pay for 6 months,save your money you might have some fees after they come back with better rates .

The Banks are under no legal obligation, at this time, and to my knowledge to ever actually have to modify the terms of a mortgage or note. What is important to know is that all communications with the Bank should be followed up with written confirmation of the same. The fact of the matter is that many people, if not most assume that if the Borrower is communicating witht the Bank, the Bank is no longer foreclosing on the property. The opposite is true. The Bank's remedy for someone falling behind in payments is to foreclose on the property. In Illinois it is common to see the Bank start foreclosure proceedings after four to six missed payments. Please consult an Attorney versed in this specialized area of law in your state and you are welcome to visit Sulaimanlaw.com for an in depth discussion of this and other foreclosure related issues. Thank You and Good Luck.