efe2023,
There's a very good chance that the problem stems from bit fields (yes/no fields in Access) that have null values. Try this. Create a query that pulls a single string or numeric field. Try to edit the field. If it works, expand your list of fields returned by the query, excluding yes/no columns. You will probably find that you can edit those fields.
To solve the problem in a way that allows you to query and edit the bit fields, you will need to do some SQL coding. You can do it in SQL Server Management System (SSMS) or in a passthrough query. What you need to to do is update any null value in a bit field to be either 0 or 1. You'll have to choose which is the best option for each column that needs this fix.
Here's some sample code, but you'll need to substitute the table and field names as needed.
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UPDATE [dbo].[Customer]
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SET [Active] = 0
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WHERE ACTIVE=NULL
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If you're not familiar with SSMS, just create a pass-through query with the same connection string you use in your ODBC table connections.
Jim