An outside collaborator receives access to a project folder. Months after the work ends, that access still exists. These leftovers are easy to create when permissions receive attention only during setup. A manageable review begins with who still needs access for which remaining task, rather than indiscriminately removing everyone.
Keep a small record with an owner
For a shared workspace, record its name, responsible person, invited guests, and the purpose of the collaboration. Add a trigger for the next review, such as project completion or a role change. A detailed list of every file ever sent is not always necessary. What matters is that someone can assess the remaining permissions.
Distinguish a named invitation, group membership, and a link that additional people may use. These routes can exist at the same time. Removing one invitation therefore may not close every route to the material. Ask the person managing a group about unclear rights rather than recording a review as complete when it is not.
Check the container and then the individual item
Permissions may come from a parent folder or workspace. Google Drive explains how access changes and folder permissions interact. Read the current guidance for the system you use and inspect the displayed origin of a permission. Someone listed on a file may need to be managed through its parent location.
Then check exceptions: individually shared documents, additional links, and files outside the expected project folder. A small sample can reveal mistakes, but it does not replace a full review when one is required. Record which areas were actually examined so a limited check does not become an unsupported claim about all data.
Make targeted changes and verify them
Before removing access, clarify whether a handoff or approval is still pending. Reduce permissions to the needed scope and remove sharing that no longer serves a purpose. Verify the result using an authorized account with the relevant rights, not only your owner view. Check whether other access routes remain.
Briefly record the date, change, and unresolved questions. Changing permissions does not automatically delete previously downloaded copies. Where those copies matter to the collaboration, handling them requires a separate agreement. For the next project, reduce cleanup work by planning access setup and closure together from the start.