How can we edit user rights?

Hi! 

We are trying to edit user rights. Specifically, what we are trying to do is change the transaction prior periods from view only to full access so that our users can edit prior transactions if needed. 

We are following the steps here

https://support.na.sage.com/selfservice/viewContent.do?externalId=12195&sliceId=1

  1. Select MaintainUsers, and then select Set Up Security

Note: If setup security is greyed out, refer to Article ID 10716: Set Up Security option is grayed out

  1. Select User Name you wish to edit, and then select Edit User's Rights. If using Quantum Accounting, select Roles List tab.

Note: If using Quantum Accounting, you can also edit a role's access on the View/Edit Role button; changes made to a role will apply to all users set to use that role.

  1. Select Administrator, Full Access, Selected Access, or select None
  2. Select Save if selecting Administrator or Full Access
  3. If choosing Selected Access, select Next and the Selected Access window will open
  4. In the Selected Access screen, set the desired user access to the different areas, and then select Save
  5. If desired, repeat for other users
  6. Click Close

This being said, every time we try, it says 

Eventually, it will let us go in and view the permissions, but we need to make changes. We have gone to the user login manager and made sure that no one else is logged in. On the file server, we have also gone in and disconnected all other computers that are even accessing the file. In fact, I went as far as to unshare the Sage (peachw) folder with everyone except our CFO who needs to make these changes. We still cannot get in. 

We're just going to have everyone shut their computers tonight and try to make the change after hours. 

Does anyone have any solutions? 

Release: Sage 50 Quantum Accounting 2020
Build: 27.1.00.0154
Serial Number: [REDACTED]
Customer ID: [REDACTED]
Installed Tax Service: 20180102
Plan Level: Sage Business Care, Auto-renews on: 2/6/2021