MS Acccess, SQL can't change data type, details in description?

Question

SQL

There is a field schet_rest (account balances), it is text, there are 20,000 lines, now for the correctness of queries, you need to make the data type numeric or monetary. The problem is that it is not possible to change the data type. One of the versions in the help is that "file lock limit exceeded" MaxLocksPerFile . Tried to do as it is written in the help. (Find the MaxLocksPerFile setting in the Windows Registry Editor (regedit.exe) and increase its value. The MaxLocksPerFile setting is located in the following key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\12.0\Access Connectivity Engine\Engines\ACE) did not help.

Answer 1

In my opinion, it's easier to create an additional field of type numeric or monetary. Transfer data from the old field with conversion. Delete the old field, rename the new one to the old one.
If you don't know how to write a query:

UPDATE таблица
SET <Новое поле> = CAST(<старое поле> as <тип данных>