AssembloERP
Every vendor says migration is easy. What they mean is that the import script works. What you are worried about — will my numbers still tie, will my CA be able to file, will the godown know what to call things — is a different job.
Here is the plan we actually run, including the parts that go wrong.
First decide what you are migrating
The single biggest mistake is trying to bring five years of vouchers across. Do not. Migrate the state of the business, not its diary.
| Migrate | Leave in Tally (archived, read-only) |
|---|---|
| Item masters with one agreed code each | Historical sales and purchase vouchers |
| Customers & suppliers with GSTIN, terms, credit limits | Old journal entries |
| Chart of accounts / ledger groups | Prior-year financial statements (export as PDF) |
| Opening balances as on cut-off date | Voucher-level narration history |
| Stock as on cut-off, by item, batch and location | Cancelled and draft entries |
| Open receivables and payables, invoice-wise | Anything you have never once looked up |
The field-by-field mapping that matters
Item master
Tally's stock item carries name, group, UOM, GST rate and HSN. In an ERP you will also need: stocking UOM versus purchase UOM, reorder level, whether the item is batch or serial tracked, and whether it is a bought-out part, a manufactured item or a job-work input. Those four fields do not exist in your Tally file. Someone has to decide them, item by item, before import.
Ledgers
Ledger groups usually map one-to-one. The friction is that operations people want cost centres and product-line reporting that your Tally chart of accounts never had. Add the dimension at migration, not six months later.
Parties
Duplicates are guaranteed — the same customer under two spellings, one with GSTIN, one without. De-duplicate on GSTIN, then on phone number, then by eye.
Opening stock
Quantity is easy. Valuation is where people get hurt: decide your method (FIFO, weighted average) and make sure the opening value matches the closing value in your last Tally balance sheet, to the rupee. If it does not tie, stop and find out why before go-live.
Four things that never transfer cleanly
- Your team's habits. Twelve years of keyboard shortcuts. Budget for genuine frustration in week one, and pick your calmest senior person as the internal helper.
- Narration-based knowledge. "Rate revised as discussed" in a voucher note is knowledge that lives nowhere else. Extract the important ones into proper fields — price lists, customer terms — before the switch.
- Custom TDL reports. Any Tally customisation your CA wrote will need rebuilding as ERP reports. List them early; there are usually two that genuinely matter and five nobody has opened in a year.
- Unposted reality. Material lying with a job worker, sales returns not yet booked, samples out. Reconcile them before you take opening stock, or you will inherit variance on day one — the same variance we catalogue in stock versus books.
The parallel month
Run both systems for one full month. Yes, it is double entry, and yes, it is worth it.
- Week 1: enter everything in both. Reconcile daily on stock movement only.
- Week 2: reconcile stock and sales. Fix master gaps as they surface.
- Week 3: add purchase and payments. Compare GST summaries.
- Week 4: close the month in both. If the two closings tie, you are done. If not, the difference is your remaining process gap — find it now, not in October.
Go-live checklist
- Opening trial balance in the ERP matches the last Tally balance sheet.
- Opening stock value matches, by item class.
- Open receivables tie invoice-wise, not just in total.
- One person named as data owner, with authority over item codes.
- GST settings verified against a test invoice — including e-invoicing if you cross the threshold, which we cover in the compliance checklist.
- Tally file backed up twice, in two places, and set to read-only.
- A named fallback: who to call on day one, and what you do if dispatch stalls.
If you would rather someone else carried this, that is exactly what our scoping call covers — we map your masters and tell you what the clean-up looks like before anyone talks about software. Start there.
