When you dispute an entry on your credit report and send a dispute to the credit bureau, it has 30 days to respond. That timeline is part of the Fair Credit Reporting Act and ensures that errors don't remain on your record permanently. However, while the short time period may cause some entries to fall off your credit report, that doesn't mean they'll stay off.
30-day Window
Credit bureaus are obligated to take disputed entries off of credit reports after 30 days unless the creditor can prove the entry is valid. Even if the entry is valid it will still go off of the credit report if the creditor doesn't verify it in time. That doesn't mean the entries are gone for good, however. If the creditor subsequently verifies the entry, the entry goes back on the credit report. This might happen when a credit card issuer that reports monthly waits to send the verification until the next reporting date.
Timeline May Change
If the creditor claims a negative entry on your credit report is valid and provides evidence to support that view, the credit bureau won't remove the entry from your report. In this case, you'll have to take additional action to prove the creditor is mistaken and that the entry doesn't belong there. This can take considerably longer than 30 days. Write another dispute letter detailing why you think the entry is not valid. Next, mail the letter to both the creditor and the reporting bureau. Let them know you are also sending copies to the Better Business Bureau, Consumer Financial Protection Bureau and perhaps your state attorney general. In some cases you may need to take legal action to finally clear the item from your records.