Troubleshoot Order Split

The order was not split

Work through the decision path in this order:

Order Split is enabled in the quote's store scope.
The cart resolves to at least two vendor and source groups.
Every required vendor value is present, or the missing-vendor fallback permits grouping.
The selected payment method is allowed.
MSI and source fallbacks do not select Create Single Order.
Every split quote can still use the selected payment and shipping methods.

Several fallbacks deliberately submit the untouched original quote. A successful single order can therefore be the configured outcome rather than a calculation failure.

Checkout is blocked

Read the displayed SKU or method message first. Common causes are:

a missing vendor value with Block Checkout
MSI being unavailable with a blocking fallback
no single source covering the requested quantity
a disallowed or invalid payment method
a shipping method unavailable to one split quote
mixed totals modes
an invalid base-suffix format or exhausted number-conflict retries

Correct the underlying data or choose a deliberate fallback. Do not switch every error to Create Single Order without checking why the split plan is incomplete.

One supplier produced several orders

When MSI is enabled, vendor and source together form the key. Products from one supplier can produce several orders when Magento resolves different sources.

Also compare the raw option values. Labels that look similar may be different attribute options.

A configurable product reports a missing vendor

Set the vendor value on the visible configurable product, or ensure the selected child values resolve to one common option. Conflicting child vendor values are treated as missing.

The selected shipping method disappears after splitting

The method must be available after each smaller quote recollects shipping rates. Check destination, cart thresholds, item restrictions and any Shipping Conditions rules against each group.

Split totals do not match expectations

First confirm that all three totals settings use the same mode.

In Recalculate mode, evaluate promotions, free-shipping thresholds and tax on each result independently.
In Proportional mode, compare the sum of the split totals with the original quote and allow for the final order carrying the rounding remainder.

The orders may exist while registry recovery is pending. Check Admin notifications, Magento cron and log entries beginning with OrderSplit:. The recovery job runs every 15 minutes.

Do not recreate the customer order merely to restore the relationship grid.