An MSP posted this in the HubSpot Community on 23 February 2024, describing what happened after they turned on two-way sync between HubSpot and ConnectWise:

"This ended up creating thousands of duplicate companies in ConnectWise, We currently have over 10,000 more contacts and 7,000 more companies"

That is not a rounding error. That is a PSA database that is now unreliable for anything: reporting, billing lookups, ticket routing, contract renewal. Every one of those extra 7,000 companies has to be found and merged by hand, and merging companies in ConnectWise is its own multi-step chore, not a button.

Here is the part that should worry you more: this is not a rare failure. SyncSmart, one of the third-party sync vendors, says it plainly in their own marketing copy:

"The most devastating error users report is the creation of thousands of duplicate companies in ConnectWise when enabling two-way sync."

That is a competitor conceding the failure mode in their own materials. When the vendors selling you the fix admit this is the most common way their category breaks, believe them.

Why it happens

The root cause is boring and that is exactly the problem: most syncs match companies by exact string comparison. "John Smith LLC" and "John Smith, LLC" are, to a naive matcher, two different companies. So is "Acme Inc." versus "Acme Incorporated" versus "ACME INC". Every inconsistency your sales team, your PSA import, or a client's own signup form ever introduced into either platform's company name field becomes a brand-new company record the moment two-way sync is switched on. Turn on sync across a few thousand existing records and the small inconsistencies that were harmless while the two systems were separate become thousands of duplicate rows overnight.

What actually fixes it

Matching has to be normalized, not exact: strip punctuation and casing, compare against the website domain as a second signal, and treat the result as a candidate match, not an automatic write. That is what HubConnector's duplicate preflight does. Before your first sync ever runs, it scans both platforms, shows you exactly which records it thinks are the same company, and asks you to approve the links. Nothing gets created until you say so. After that first pass, every record is tracked in a cross-reference table so it can only ever be linked once, in either direction.

If you want to see what a sync would actually create before it touches your PSA, HubConnector is opening a waitlist at hubconnector.io.