How to fix missing or duplicated trades

Find out why trades are missing or repeated and fix it, depending on whether they come from MT4 / MT5, an exchange or a CSV file.

Steps

Open Trades, click Filters and choose the Account and dates you are checking.
Compare the list with your platform's history to see what is missing or repeated.
Missing from MT4 or MT5: raise HistoryDays in the Expert Advisor inputs to cover the period and attach it again.
Missing from an exchange: in Accounts click Sync now on that key.
Missing from a CSV: import the file again and check the count of rows skipped in the result.
Repeated from a CSV without an ID: click the trash icon on each extra trade.
Confirm with Yes, delete.

Trades with a ticket or ID (MT4 / MT5, exchanges, cTrader, CSV with an ID column) are updated, never duplicated, when they are sent again.
Exchanges only import pairs quoted in USD or a USD stablecoin, and some only keep a few months of history. Check the exchange's guide.
A sale of coins bought before the imported history shows a $0 result, because its buy price is unknown.

Tell us what you were trying to do and what happened. A person replies by email, usually within one business day.