Several ATM users have reported faulty transactions after RBI's notification to make inter-bank ATM transactions free of charges was issued on April 1, 2009. Commenting on the situation, an HDFC Bank official said, "There's a glitch in the system that has temporarily inconvenienced customers. But no one has lost money on account of void transactions." The faulty transactions include failed transactions, account debits against no cash withdrawal and void transactions.

A void transaction is a transaction where the user request is not completed and ATM does not dispenses cash. It has been found that void transaction in many case have been associated with account debits.

Though wrong debits have been corrected and amount has been credited to the respective accounts, it comes at the cost of customer trust. The problem has vexed customer to the extent that many have restricted the use of ATMs of banks other than their own. In response to the problem, an ICICI official said, "There is a problem that is happening now and again when customers from Kolkata use ATMs of other banks in Siliguri, Durgapur, Asansol or other towns. We follow up each case, verify the transaction details with the other bank and try to credit the amount within two-three working days."

The problem is more frequent with ATM machines of smaller banks like Apex, IDBI; though big names like SBI, HDFC and ICICI are also affected by it.

Experts reasoned defects in functioning of National Financial Switch (NFS), a network technology that enables synchronisation of inter-bank ATM transactions. NFS is the largest network connecting 16,891 ATMs across country and handles an average of 75,000 transactions daily.