1. Hiring a US salesperson before the system exists

This is the single most common failure mode. A US rep is hired on day one, lands without a playbook, without inbound leads, without product positioning that resonates locally, and without anyone above them who has sold in the US. Nine months later, the rep is let go and the conclusion is 'the US is hard.'

The fix: prove the system first — usually founder-led or via a fractional/outsourced partner — and hire only after 8–12 qualified opportunities exist. The first US hire is then concrete: you know the ICP, the objections, the buying process, and the kind of seller who wins.

2. Copy-pasting European messaging

European messaging is often built around capability ('what we do'), credentials, and relationship. US buyers want outcomes ('what changes for me'), proof, and a fast path to a next step. Messaging that sounds professional in London or Helsinki frequently reads as slow or vague in New York or Austin. The first 30 days in any US entry should include a full messaging rewrite, not just a translation.

3. Under-investing in US email infrastructure

US inbox providers (Gmail business, Outlook 365) apply tighter spam filtering than most European ones. Sending into the US from a European domain that hasn't been warmed for the US, with European IPs, and with sequences that work fine in Europe, often produces sub-2% reply rates. The fix is US-based sending domains, US IP warm-up, careful volume ramp, and inbox rotation.

4. Underestimating US enterprise sales cycle length

US enterprise sales cycles for a $50K–$500K ACV product typically run 6–12 months, not the 2–3 months many European founders are used to. Procurement is heavier, security review is heavier, the buying committee is larger. Forecasts that assume European cycle length consistently miss.

5. Staffing US coverage with European working hours

A US prospect who replies at 10am Pacific is replying at 7pm Helsinki. If the reply gets handled the next morning, that's a 15-hour gap — long enough for the prospect to lose interest or take a competitor's call. Either a US-based responder, a partner running US-hours coverage, or a strict response SLA enforced on the European team.

6. Chasing the largest logos first

It's tempting to target Fortune 100 first because the logos look great on the slide. But the first US deals should usually be mid-market — $1B–$10B companies, faster decisions, smaller buying committees, more willing to take a risk on a foreign vendor. Use mid-market wins as proof to credibly approach enterprise.

7. Treating US expansion as a marketing exercise

Booth at a US conference, a few PR placements, a website refresh — and then waiting for inbound. US entry is a sales-execution problem. Marketing supports it but does not replace it. The companies that succeed are running disciplined outbound from day one.

8. Not budgeting for the 6–9 months before first revenue

Most European founders budget for 'launching in the US' but not for the 6–9 months of cash burn before meaningful revenue closes. The system has to exist before deals close, and US enterprise deals don't close in week 6. Plan cash for at least 9 months from launch.