Why are fields editable when they should be read-only?

When a Salesforce field remains editable even after you mark it as read-only on the page layout, the cause is usually not the layout itself. This usually stems from profile permissions taking priority over page layout properties.

Most teams remove field editing at the page layout level to meet business requirements. These are the usual steps:

1. Go to the Object Manager and select the desired object to edit.

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2. Select Page Layouts.

3. Highlight the field you want to change, then open its properties.

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4. Edit the field properties and click OK.

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If the field stays editable after you apply the layout, Salesforce is honoring a profile-level override.

Review the user’s profile settings:

1. Find the user’s Profile and click Edit.

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2. Go to Administrative Permissions.

3. Look for Edit Read Only Fields.

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If this checkbox is selected, the user can edit fields even when the page layout marks them as read-only.

Clear the Edit Read Only Fields permission on the profile.
This restores control to the page layout and enforces your read-only rules.

Profile permissions take priority over page layouts.
When a field behaves unexpectedly, always check the profile settings.