How to Review Software UAT and Deemed Acceptance Before Go-Live

Bryn, Ops at a 20-person UK proptech, is about to treat a ten-day UAT window as protection. Knowing how to review software uat deemed-acceptance before go-live is a 25-minute hunt: name the spec Exhibit, start the clock on readiness not a “delivered” email, keep a severity table, kill silence and production-use deemed acceptance, then keep a written reject path or walk.

September 2026. English law; exclusive courts of England and Wales. The packet — the exact file set that will be signed — is a vendor SOW for a tenant-onboarding portal: clause 7.1 ten (10) business days from Vendor’s “delivered” email; 7.2 “reasonably satisfactory to Customer”; 7.3 silence or production use = deemed accepted; 7.4 Customer prepares all UAT scripts. No severity table, and last week testers sat idle — no test tenancies. AE Slack: “Ten days is market. Go-live Friday.” The hidden risk is silence already deeming Friday.

A ten-day clock from a “delivered” email, plus any production use equals accepted, is vendor-favourable paper. ContractKen (live 2026-09-21) labels that stack as the vendor-favourable ladder; a 5 or 10 business-day silence trigger can deem acceptance before a single end-to-end test. Pinsent on SAM v Hedley [2002] EWHC 2733 (TCC): the software was defective and had never worked properly — Hedley still lost the money-back path because it missed the written, criterion-referenced reject machinery.

Disclaimer: Checkory provides AI support, not legal advice. Consult a qualified lawyer for binding decisions.

What does pass/fail actually require — a named spec or “reasonably satisfactory”?

Pass/fail has to be a test a third party can run against a named spec, not a vibe. Circle “reasonably satisfactory to Customer.” Slack “not happy” is not a valid rejection. Log the Exhibit — attached schedule or appendix — of numbered criteria, or write “reasonably satisfactory — fail.”

Do: map scripts to the signed specification. Don’t: leave “done” to whoever is angrier later. GetProjects: “to the reasonable satisfaction of the Client” is not a test. Talk Think Do (8 June 2026): rejection must identify where it does not conform. For example, sales-demo promises that never made the SOW usually do not become the test.

How do you start the UAT clock — readiness, or a “delivered” email?

The clock starts when the build is actually testable, not when someone emails “delivered.” Circle ten (10) business days from Vendor’s email. Last week Bryn’s testers sat idle because the UAT tenant had no test tenancies. Write Notice of Readiness plus environment, data, and named testers, or “delivered email — fail.”

Do: start from written ready-for-testing notice and pause while blocked. Don’t: let ten days burn on an empty tenant. ReviewMyContract: 15 business days is reasonable; 5 is not for complex deliverables. Sprintlaw UK (10 June 2026): a five-day window “may look neat” and still be unreal for multiple users and integrations.

How do you treat a critical defect versus a snag list?

A severity table stops a truncated label stalling Friday and a crash shipping on a snag list. Critical — crash, data loss, payment or onboarding path dead, security — blocks acceptance. Minor goes on a punch list with an owner and a date. No table on Bryn’s paper is a fail.

Do: reject only against named severity. Don’t: let any bug block, or let a Sev-1 ship as “we’ll log it.” Sprintlaw AU (3 June 2026) (structure, not England-and-Wales statute): any critical blocks; minors if logged and dated. developer.law (2026): S1/S2 block; S3/S4 punch list. Wezardapp (26 August 2026) is a meeting bar, not a deemed-acceptance clause. Still put the rule in the SOW.

Does silence or production use deem the portal accepted?

Silence and production use are triggers, not courtesy. Clause 7.3 deems the portal accepted if Bryn does not issue a written rejection in ten business days, or if anyone uses it in production. Log 10-day silence plus any-prod-use as fail unless a realistic window, named inbox, pause, and a production-use carve-out exist.

Do: kill any-production-use, or carve pilots, parallel run, and data-load. Don’t: treat an inbox miss as a courtesy reminder. In practice, a Friday parallel run is the trap AE already named. SAM v Hedley colour: miss the written reject and the money-back path can die even if the software never worked. Sale of Goods Act 1979 s.35 is goods colour, not a custom-build UAT statute; SGSA 1982 s.13 implies reasonable care and skill for services; it does not insert a 10-day silence trigger. Put the reject path in the paper.

Is this the whole-SOW tour, or the defects clock after acceptance?

This hunt is whether Acceptance happens before Friday, not the rest of the SOW and not the repair clock after Acceptance. Stay on clause 7. The MSA — master services agreement, the frame vendors hang order forms on — only matters here if it sets a default acceptance.

If the fight is deliverable counts, exclusions, change orders, or payment triggers, that is a different hunt: statement of work review checklist before signing. If the fight is how long they must fix after Acceptance, that is a different clock: how to review a defects-liability period after acceptance. Do: one sentence each, then come back. Don’t: spend counsel — a qualified lawyer, not the chatbot — on the whole SOW or a 30-day DLP while clause 7 still deems Friday.

When to keep a written reject path, and when to walk?

Keep a written reject path only if the log shows a named spec Exhibit, a readiness clock with pause, a severity table, narrowed deemed acceptance, and a reject notice testers can send this week. Walk if 10 BD from a delivered email, reasonably satisfactory, silence-or-prod-use, and Customer-only scripts remain as a package.

Success bar: a one-page log plus one sentence that would pause Friday. Bryn already has it. Workflow: named spec pass/fail → readiness clock (not delivered email) → severity table (critical blocks / minor snag) → kill or narrow silence and production-use deemed acceptance → not B16 / not B76 → written reject path / walk. Optional: upload the same PDF to document analysis for a first-pass — a machine extract before a human reads every page — then a named human still opens clause 7 and verifies every High flag — a high-severity extract a reviewer still opens. Do not mark the paper ready because ten days “is market.”