When doing a bank reconciliation, it takes a long time to load transactions
This is common when there are years of bank transactions in the database. It can take a long time to load them all. Clearing Bank History is the only thing that will address this, but it is largely harmless because most of the information in Bank Services comes from other modules.
To clear history, first back up the company database. See Backup using DBDump for help with backup procedures.
Nex, run Bank Services -> Bank Periodic Processing -> Clear History. Clear Bank Transactions for all banks up to a selected date. When this process has completed, speed when doing reconciliations should increase significantly.