Plenty of migration tooling — ours included, at first — is built around a clean assumption: one PC, one user, one mailbox. Scan Outlook, find the account, migrate it. It works right up until it meets a shift computer with three POP3 accounts configured in the same profile, because three different people clock in on it over the course of a week.
The failure mode isn't dramatic. It's a machine that sits at "multiple accounts found, needs manual mapping" indefinitely, because the tool has no way to tell which of three real, legitimate accounts is the one to migrate — because the honest answer is all three, separately.
The more dangerous failure mode shows up once you try to "fix" the first one by picking any account and running with it: if the export and import steps aren't careful about which files belong to which account, mail from one person's PST can end up imported into a colleague's mailbox. On a shared PC, the backup folder holding exported PSTs naturally accumulates files for every account that's ever been migrated from that machine — a naive import step that scans "everything in the backup folder" instead of "exactly this account's file" will happily import someone else's mail right along with it.
What actually needs to happen is more deliberate: detect up front when a machine has two or more scanned mailboxes that each independently match a real mapping (not one legitimate account buried among unrelated noise — genuinely separate, intentional entries). When that's the case, treat it as N separate migrations that happen to share a PC: scan, export, and import one account fully before moving to the next, and hand the import step an explicit list of exactly that account's exported files rather than trusting it to figure out the right subset of a shared folder.
It costs more code than the one-PC-one-mailbox happy path. It's also the difference between a shared PC migrating cleanly and a shared PC quietly mixing two people's email together, which is the kind of bug you find out about from an angry phone call, not a log file.