Negative quantities in Thrive typically occur when products are updated in the point-of-sale system rather than in Thrive.
Once Thrive is installed, we strongly recommend only making all changes, updates, and additions in Thrive Inventory, and not in your provider's system.
For a more detailed explanation, check out this article: How Thrive Syncs
Correcting negative quantities
If the quantities are correct in your integration (e.g. Square, Clover, etc.), that inventory information can be imported over to Thrive Inventory to correct our counts.
Follow this guide to import counts from your provider.
This will pull in exactly what's in the integration, right or wrong, so be sure the information in your provider's system is correct.
If neither Thrive Inventory nor your integration has accurate quantities, corrections should be made only in Thrive.
We have a guide to Updating Quantities, Costs, and Prices.
Do a manual count before entering the inventory information into Thrive. Use our tools for reconciling to get an accurate physical count.
Another option is to update quantities via a spreadsheet upload using the Bulk Upload tool.
Avoiding negative quantities going forward
To avoid negative counts, make all changes to your quantities in Thrive and...
Make sure your Sync Settings are both Enabled on that integration.
Set Alerts so you are notified as soon as inventory starts to run low.