Carry an asset's existing book balance in from the system it came from, instead of letting the app derive one.
Most assets do not start their book life in DepreciationPro. They arrive part-way through, carrying a balance taken somewhere else. The book record takes that balance directly rather than recomputing it.
Enter the balance
On the asset's GAAP Book tab, under Accumulated Depreciation (Import/Adoption):
Enter the Accumulated Book Depreciation figure from the prior system.
An As-of Date field appears once that amount is above zero. Enter the date the balance was taken through.
Tick Prior depreciation imported.
Click Save GAAP book.
From then on the figure you supplied is the starting point, and the app depreciates forward from it.
Why the checkbox matters
It is the switch between two behaviors.
Ticked, with an amount entered, your accumulated figure is used as given and carried forward.
Unticked, the app derives prior accumulated depreciation itself from the in-service date and the monthly amount.
Both parts are needed. Ticking the box with no amount entered leaves the app deriving the figure, the same as if the box were clear.
A supplied balance is used as given
The app does not recompute your figure, second-guess it, or cap it at what the life would imply. That is what makes a faithful conversion possible, and it is why the number is worth checking once at the point of entry rather than a year later.
Two things to know about the schedule
The As-of Date is recorded with the balance, not used to reset the schedule. The months the app charges still come from the useful life and the in-service date.
The remaining life is whatever the useful life and in-service date imply. An asset carried across mid-life finishes on the schedule its original life sets, not a fresh one starting today.
Doing it in bulk
An import that carries a book accumulated-depreciation column sets all of this for you, on every row at once. See Import assets that already carry book columns.