Dedicated accounts may not be used with the GAAP feature
Generally Accepted Accounting Practices (GAAP) do not allow the use of dedicated accounts. Therefore, when the GAAP feature is turned on, the software does not allow you to add any new dedicated accounts, and any previously used dedicated accounts must be archived after ensuring they have a zero balance.
The reason dedicated accounts are not GAAP compliant is dedicated accounts are not income or expense accounts and are not displayed on the Statement of Activities. The absence of income and/or expense accounts distorts the financial statements. For the official pronouncement, please see Understanding the New FASB Accounting Standards - An Overview.
(For clarity: This chart or something similar may help you to understand the changes from dedicated accounts to restrictions)