Creating a new purchase order throws an unexpected error - No special account of type "PurchOrd" exists.

1.  Navigate to Setup > Company > Enable Features > Transactions tab and uncheck Purchase Order/Estimate/Sales Order and click Save.

2.  Go back to the same page and enable the same feature you enabled in step #1 then hit Save.

Note:

Delete All Data initially removes ALL Non-Posting Type of Accounts.  We need to disable and enable one of the Non-Posting transaction features such as Estimates that will not affect other features.  This will bring back ALL Non-Posting Type of Accounts on the list of accounts.