Two ways to move a Tally company exist, and people pick between them by habit. One packs the data through Tally itself; the other copies raw files through Windows. Here is what each route really does to your data, and the honest rule for choosing.
Ask ten accountants how to move a Tally company and half will say take a backup, half will say copy the data folder. Both believe they are right - and both can be, in different situations. The difference matters most exactly in the case this page is about: handing data to a client, where a silent mistake lands on someone else's books.
Both routes can work. Only one of them checks the data while it moves.
When you run Backup from Tally itself (Alt + Y in TallyPrime, Alt + F3 in ERP 9), Tally reads the company through its own engine and writes one compressed .tbk file. The company is packed consistently - masters, vouchers and indexes together - and the restore on the other side rebuilds the company through Tally again. That round trip through the software is exactly why this is the safe route for anything that leaves your office.
Copying the numbered company folder from C:\Users\Public\TallyPrime\Data (or the ERP 9 Data folder) copies the raw files - all of them, in whatever condition they are in at that second. If the company is open, some files hold half-written data. If one file in the set fails to copy, the folder looks complete but is not. Windows Explorer will not warn you about either problem.
A folder copy also creates a practical trap on the receiving PC: every company folder has a number. If the client's Data folder already contains a folder with the same number, pasting yours either overwrites their company or has to be renumbered by hand - a mistake here can destroy the wrong company's data.
.tbk backup. It is one file, it is consistent, and the restore handles numbering on the other sideIf you do use a folder copy, shut the company, exit Tally, copy the entire numbered folder, and on the other PC paste it into the Data folder under a number that is not already in use - then open Tally and confirm the company appears in the Select Company list with the right name and financial year.
Backup, transfer and restore shown live on screen, with the full knowledge and installation details.
Watch Full VideoNot always - it is a valid way to move data on your own machines when Tally is fully closed. It becomes dangerous when the company is open during the copy, when files are missed, or when the folder number clashes with an existing company on the receiving PC. For handovers to another person, the .tbk backup is the safer route.
It is the single backup file Tally creates from its Backup option. It contains the complete company - masters, vouchers and settings - and is restored through Tally's Restore option, which rebuilds the company on the target PC.
Do not paste over it. Either restore from a .tbk backup instead (the recommended fix - restore manages the placement), or rename your copied folder to a free number before pasting. Overwriting a numbered folder replaces that company entirely.