C=315 — what to cross-check immediately: Run these reports and compare against external records: (1) Payroll Summary report (Reports → Employees & Payroll → Payroll Summary) — check gross wages, deductions, and net pay per employee against paystubs or bank transfers. (2) Payroll Liability Balances report — compare against actual tax deposits made (check bank records). (3) Employee Earnings Summary — verify YTD totals are correct before any W-2 processing. If discrepancies appear between QB reports and external records, the C=315 corruption has already affected payroll calculations that need manual correction before filing.

Corrupt Payroll Item Data

Primary C=315 cause — a payroll item (salary, hourly wage, tax item, deduction, company contribution) has corrupted internal data. When QB tries to calculate payroll using a corrupted payroll item, it flags C=315. The Verify Target in QBWin.log identifies the specific payroll item — navigate to Lists → Payroll Item List to find and repair or recreate it.

Damaged Employee Payroll Records

An employee's payroll setup record — their tax withholding settings, direct deposit info, pay schedule, or YTD earning records — is corrupted. C=315 appears when QB tries to process or verify that employee's data. Opening and resaving the affected employee's record sometimes corrects minor field corruption.

Pay History Data Corruption

The pay history records (YTD earnings, tax withholdings, deductions accumulated) for one or more employees are corrupted. This is particularly serious as pay history drives W-2 calculations. Corruption here means W-2 amounts may be wrong even if recent paychecks look correct. Compare W-2 preview totals against actual payroll deposits.

Payroll Tax Calculation Table Damage

The internal tax calculation tables used by QB to compute federal and state withholding are damaged. C=315 flags this when Verify detects inconsistencies in the tax data structures. Running the payroll update (Employees → Get Payroll Updates) refreshes these tables from Intuit's servers, which can resolve this cause without file repair.

Interrupted Payroll Processing

A system crash or power failure during paycheck creation or payroll liability payment left payroll records in a half-written state. QB created some payroll records but not all the associated liability entries, or wrote the paycheck but not the corresponding tax withholding records. C=315 flags the resulting inconsistency during Verify.

Payroll Liability Account Corruption

The payroll liability accounts (Federal Tax Payable, State Tax Payable, etc.) have corrupted balances that don't match the underlying payroll transactions. This causes the Payroll Liability Balances report to show incorrect amounts — the visible symptom that often leads to discovering C=315 in QBWin.log.

METHOD 1 Run Payroll Update + Read QBWin.log + Verify/Rebuild Primary C=315 repair sequence

METHOD 2 Recreate Damaged Payroll Item or Employee Record C=315 persists on specific payroll item/employee

METHOD 3 Run File Doctor + Restore from Backup C=315 LVL_SEVERE_ERROR or widespread payroll damage

Can C=315 affect W-2s and tax filings?

Yes — this is the primary concern with C=315. Payroll data corruption can affect the accumulated YTD earnings and tax withholding totals that QB uses to generate W-2s. If pay history records are corrupted, QB may calculate incorrect box amounts on W-2s even though individual paychecks look correct. Before filing W-2s or any payroll tax forms (941, 940, state forms), verify QB's totals against your bank records: sum all net payroll deposits and compare against QB's net pay total; sum all tax deposits made and compare against QB's tax liability total. Discrepancies indicate the corruption has affected calculated amounts that must be corrected before filing.

Why does running the payroll update sometimes fix C=315 without file repair?

QB's payroll update (Get Payroll Updates) downloads and reinstalls the payroll tax tables and payroll item definitions from Intuit's servers. If C=315 is caused by corruption in these downloaded components — the tax rate tables, payroll item structures, or agency definitions — the update overwrites the corrupted components with fresh downloads from Intuit. This resolves the C=315 without requiring file repair because the corruption wasn't in the company file itself, but in the payroll data components that are periodically refreshed from Intuit's servers. This is a payroll-specific repair path not available for other C= codes like C=47 or C=224.