What are the implications of changing organization-wide defaults and how do you plan and execute such changes to ensure no disruption of sharing access across different user groups?

Changing organization-wide defaults (OWD) in Salesforce has significant implications for data security and sharing access, and must be handled carefully to avoid disruptions and potential data leaks. OWD settings determine the baseline level of access users have to each other's records, and modifying them can drastically change how users see data across the organization. Therefore, any changes to OWD settings require careful planning, impact analysis, and meticulous execution.

The most immediate implication of changing OWDs is the potential alteration of data visibility. For example, if the OWD for the 'Opportunity' object is changed from 'Public Read/Write' to 'Private', users who previously could see and edit all opportunities may suddenly lose access to those records they do not own or are not given explicit access through sharing rules. This change will affect all users and all existing records and can severely impact user workflows if not properly planned. Another significant implication is that changing OWDs can have a cascading effect on sharing rules. If the OWD is set to Private, then sharing rules are the primary mechanism for granting access beyond the record owner. You must check the sharing rules to make sure they are set up correctly. In addition, any custom Apex sharing logic will need to be tested after the change. This also includes any automation logic, as the ownership of records may change and that can influence how record updates take place. If the OWD is set to public read or write, then there may be concerns from the business and from a compliance perspective, as any user on the system will be able to see all records of that particular object.

Changing OWDs also has implications for performance, especially for very large organizations. When switching from a more permissive setting, such as Public Read/Write, to a more restrictive one like Private, the system may recalculate the sharing model across the platform. This can take some time depending on the number of records in the system and can have a significant impact on the overall performance of the platform for a period. Be aware that the changes to the OWD settings cannot be rolled back if a mistake has been made. Therefore, carefully planning all the stages of the changes is absolutely necessary.

To plan a change to OWD, first analyze the current sharing settings thoroughly. Before making any changes, document the existing OWD settings for each object and understand who has access to data and through which mechanism (e.g., sharing rules, role hierarchy). Use Salesforce’s built-in reporting features to identify users or roles that are currently accessing a particular object’s data and plan what changes are needed to share this data once the OWD changes have been made. If possible, use a sandbox environment to test the impact of the proposed changes. Start with a test change to the OWD and examine the outcome. Verify that users have the appropriate access to the records they need by using the ‘Login As’ feature in the sandbox to impersonate different users to examine data visibility. In this environment, experiment with different values and different settings.

Next, communicate with stakeholders across the organization. Explain the changes that are taking place, why they are necessary and what the impact will be. Provide training on the new access models and make sure that they understand how the changes are likely to affect them. This will help prepare the user base to understand the new changes. When deploying changes in production, do it during a maintenance window when usage is typically low. This will reduce the impact of the changes during a working day. Carefully schedule the OWD changes and plan enough time to monitor performance and take corrective actions if needed. After the change, thoroughly monitor the system. Monitor user access, performance, and any reported issues. Use debug logs and reports to identify areas where access may be incorrect, or there may be unexpected outcomes. Use the 'sharing hierarchy' and 'sharing access' button on record page to determine why certain users may or may not see a particular record.

In summary, when changing organization-wide defaults, take extra care, and plan each step thoroughly, keeping in mind that you cannot roll back the change once applied. Changes to OWDs can have a significant impact on the access users have to records, and by applying a well-thought-out approach and communicating all the changes to the users, any disruption to users can be minimized.