Repair Several Months of Bookkeeping Together
Yes, several months can be corrected within one bookkeeping repair project. The work should follow a clear period sequence because an error in an early balance can carry into every later month. Correcting the supported source of the problem is more useful than patching the latest total.
Find the last dependable starting point
Identify the most recent completed reconciliation and compare its closing balance with the next period. Review which accounts were active, which statements are available and when the problem first appeared. If the opening balance is unsupported, later months may look wrong even when individual transactions are entered accurately.
Handle recurring causes together
An import that duplicated three months of expenses requires a different repair plan from three months of missing sales. Group the cause, then verify the affected entries in each period. A consistent correction method can make the project more efficient, but each month still needs its own supporting evidence and balance check.
Keep a visible completion record
Track completed periods, unresolved transactions and decisions requiring owner or tax professional input. Save revised reports after the corrections are reviewed. If a change affects a year already used for tax filing, identify that separately for the tax preparer. The useful result is a connected set of supported monthly records, with clear notes about what changed, rather than a single year total that happens to match a bank balance.