Migration · 2026

Migration

How to migrate from spreadsheets to multi-channel inventory software (UK)

The practical playbook for UK sellers who've outgrown spreadsheets but are terrified of breaking everything during the switch.

9 min readBeginnerUpdated 15 April 2026

TL;DR

Audit and clean your spreadsheet before import. 80% of failed migrations are actually dirty data, not software problems.
Import as a read-only dry run first. Confirm the data looks right in the new system before turning any integrations on.
Dual-run for 7 days — keep both the spreadsheet and the new system live. Compare stock counts daily.
Turn on channel integrations one at a time, not all at once. If something breaks, you'll know exactly which channel.
Archive the spreadsheet on day 8 — don't delete. You may need it for reconciliation for the first month.

Why this matters

Spreadsheets work up to roughly 200 SKUs and 2 channels. Beyond that, stock drifts within days and oversells become routine. The barrier to moving to software isn't cost or features — it's fear of breaking the live business during migration. Many sellers who tried once and had a bad experience won't try again for years.

Goal of this playbook

By the end of this guide you'll have a safe, reversible migration path: your data in the new platform, channels integrated, and the spreadsheet safely archived — with zero downtime to your live business.

Before you start

You’ll need:

Your current master spreadsheet (Excel or Google Sheets)
A list of every sales channel you're currently selling on
API credentials for each channel (or willingness to obtain them — see our marketplace setup playbooks)
A couple of hours of uninterrupted time for the initial import

The playbook

Audit and clean the spreadsheet

2-4 hours (the biggest step)

Open your master spreadsheet. For every SKU, verify: the SKU column is unique (no duplicates, no blanks), the stock number matches a recent physical count (if unsure, do a quick stock take), cost and selling prices are populated, and there are no merged cells or text notes mixed in with numeric columns.

Duplicates are the #1 cause of failed imports. Run a quick =COUNTIF check on the SKU column.
Stock counts older than 30 days are usually wrong. A fresh count is worth the hour.
If you have variant products, ensure variants each have a unique SKU — 'Blue T-shirt (Medium)' is not a SKU.

Pitfall

Don't import SKUs you're no longer selling. Archive them in the spreadsheet first. A messy catalogue stays messy in the new system.

Map your spreadsheet columns to the platform schema

30 min

MaxInvent's import wizard auto-detects columns but always review. Map: SKU → sku, Product Name → name, Stock → quantity, Cost → costPrice, Selling Price → sellingPrice, Barcode → barcode. Any columns you don't map are ignored (safe default).

If you have multiple price tiers (retail / wholesale / pallet), map them all in one pass.
Weight and dimensions, if present, help with courier rate shopping later.

Run a dry import (read-only)

5 min

MaxInvent's import supports a preview mode — it shows what would be created without writing anything. Review the preview: are SKU counts correct, are stock totals correct, are any products flagged as duplicates. Fix anything that looks wrong in the spreadsheet, re-run the preview, and only commit when the preview looks clean.

Commit the import

2 min

Click Import. MaxInvent creates every product in the catalogue and sets the stock levels. Do NOT turn on any channel integrations yet — we want to validate the pool first.

Connect channels one at a time

30 min per channel

Start with your highest-volume channel. Connect it, pull listings, map listings to the imported SKUs. Enable order import but NOT stock sync yet — we're in dual-run mode. Orders will flow through the new system, but the spreadsheet remains the source of truth until we validate.

Connecting one channel at a time means any issue is isolated to that channel.
Typical order: Amazon → eBay → Temu → TikTok Shop.

Dual-run for 7 days and reconcile daily

15 min/day for 7 days

For a week, continue updating stock in both the spreadsheet AND letting MaxInvent track it automatically. Each morning, spot-check 10 random SKUs: does the spreadsheet count match MaxInvent's? If any mismatch, investigate before moving on.

Small mismatches (±1) are usually timing — orders that landed at midnight.
Large mismatches (5+) are a bug — find the cause before enabling stock sync.

Enable stock sync and archive the spreadsheet

10 min

On day 8, if reconciliation was clean, turn on stock sync (see the multi-channel stock sync playbook for cadence guidance). Save a dated snapshot of the spreadsheet as read-only and stop editing it. From this point, MaxInvent is the source of truth.

Pitfall

Do not delete the spreadsheet. Keep it for at least 90 days in case of VAT audits or reconciliation disputes with couriers.

How to know it worked

After following every step, you should be able to verify these outcomes:

Total SKU count in MaxInvent matches the expected count from your cleaned spreadsheet
Total stock units in MaxInvent matches the spreadsheet within 0.5%
After 7 days of dual-run, daily spot checks show no systematic mismatches
Orders from every connected channel land in MaxInvent's queue within 15 minutes of being placed

Frequently asked questions

How long does a typical migration take?+

For a UK seller with under 1,000 SKUs and 2-3 channels, budget one full day for data prep + initial import, then 7 days of low-effort dual-run (15 min/day). Larger catalogues (10,000+ SKUs) can take 2-3 days of prep. The software side is fast; the spreadsheet clean-up is the slow step.

Will I lose any sales during migration?+

No, if you follow the dual-run approach. The old spreadsheet continues to be used until you're confident in the new system, and channels stay live throughout. There is zero downtime because you never turn off your channels.

What if my spreadsheet is really messy?+

Most are. The only strict requirement is unique, non-blank SKUs. If you have 500 SKUs but only 400 have SKUs assigned, fix that first (even in the spreadsheet). Missing prices, weights and descriptions can be filled in later inside MaxInvent — they don't block the import.

Do I need to stop selling during the migration?+

No. Channels stay online throughout. The dual-run period specifically exists so the live business keeps running while the new system proves itself.

What if I want to roll back to the spreadsheet?+

You can, any time in the first 7 days. Just turn off MaxInvent's stock sync (which was never on during dual-run) and keep updating the spreadsheet. Your channels never knew about the change.

Ready to run this playbook in MaxInvent?

MaxInvent is built for UK multi-channel sellers. One stock pool across Amazon, eBay, Temu, TikTok Shop, Groupon and more — with the UK’s only native Temu courier label integration.

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Playbooks are educational content. For tax, legal or regulatory questions (especially around VAT), always consult a qualified adviser.