A method comprising: receiving, by a client application associated with a content management system, a user selection to synchronize an operating system functional folder using the content management system, the operating system functional folder being stored on a client device at a first location that is outside of a synchronized folder managed by the client application, the client application associated with a user account on the content management system, wherein the operating system functional folder is required by an operating system on the client device; after the user selection, moving, by the client application, the operating system functional folder at the first location of the client device to a second location within the synchronized folder managed by the client application; creating, by the client application, a pointer in the operating system on the client device to the second location within the synchronized folder managed by the client application; after the operating system functional folder has been moved to the second location, performing an invariant check comprising comparing a content management system record of a current state of the operating system functional folder with a client application record of a current state of the operating system functional folder and with an operating system current state of the operating system functional folder; and synchronizing the operating system functional folder with the content management system upon determining, based on the invariant check, that the content management system record of the current state of the operating system functional folder matches the client application record of the current state of the operating system functional folder and matches the operating system current state of the operating system functional folder. receiving, by a client application associated with a content management system, a user selection to synchronize an operating system functional folder using the content management system, the operating system functional folder being stored on a client device at a first location that is outside of a synchronized folder managed by the client application, the client application associated with a user account on the content management system, wherein the operating system functional folder is required by an operating system on the client device; after the user selection, moving, by the client application, the operating system functional folder at the first location of the client device to a second location within the synchronized folder managed by the client application; creating, by the client application, a pointer in the operating system on the client device to the second location within the synchronized folder managed by the client application; after the operating system functional folder has been moved to the second location, performing an invariant check comprising comparing a content management system record of a current state of the operating system functional folder with a client application record of a current state of the operating system functional folder and with an operating system current state of the operating system functional folder; and synchronizing the operating system functional folder with the content management system upon determining, based on the invariant check, that the content management system record of the current state of the operating system functional folder matches the client application record of the current state of the operating system functional folder and matches the operating system current state of the operating system functional folder.