Can I use it on two computers?

A license covers a number of activated machines, so installing on both is fine. What we'd caution against is running live strategies on two machines against the same broker account at the same time — not a licensing problem, a trading one. Both instances would be managing positions without knowing about each other, and the failure mode is doubled or conflicting orders. Use one for live and the other for research, or make sure only one is armed at a time.

Can confirm the doubled-order failure mode exists and is as unpleasant as it sounds.

My setup, in case it helps: 1. Desktop is the only machine that ever runs anything live. 2. Laptop is research only — backtests, chart reading, editing strategy files. 3. Anything I edit on the laptop gets copied over and re-run on the desktop before it goes live, so I never have two versions drifting apart. Point 3 sounds pedantic but I've absolutely fixed a bug on one machine and left the broken version running on the other.

Dumb question but does anything sync between the two installs, or do I have to move my strategy files across by hand? I keep imagining tweaking params on the laptop in a hotel and then wondering months later why my results don't line up with what I remember. Also curious whether just having a second instance open (not running anything) can cause issues, or is it purely the live-orders part?

Genuinely asking. How would you find out you're double-firing before it costs you? Order log with duplicate timestamps a few ms apart, I assume? Feels like the sort of thing you'd want to reproduce deliberately on a paper account once, so you know what the fingerprint looks like, rather than discovering it live.