Indian businessman are required to fill-in and submit their Value Added Tax (VAT) returns in a timely manner and state governments provide Microsoft Excel template to make the computation easier and automated. However, the excel form-template provided by Rajasthan state government for "VAT Form 7A" always resulted in a read-only error for "PERIOD TO" field when a user completes the "PERIOD FROM" field with correct date as shown below. This error prevents further data input impossible, the concerned authorities and helpline have no idea/solution about this. Thankfully, when my friend approached me with the issue I was able to fix this as shared ahead.
The fix is as simple as using the date format in DD-MMM-YYYY format as shown below which the sheet expects, the form designer forgot/overlooked the need to mention this crucial piece of information and even failed to notify the user about it with a proper error-message leaving users with a cryptic error message (like iTunes error codes) which makes fixing even harder.