Assuming you have a Collab enabled project. Assuming user 1 (the owner) has invited user 2. Assuming user 1 has published files. Assuming user 2 has previously downloaded the bulk of the project.

1. As user 2, start Unity.app/exe and navigate to Cloud projects.
2. Select the project that User 1 created. Download project.
3. As user 1, publish a fair amount of files (this is so user 2 can cancel at his leisure)
4. As user 2, cancel the update. Resume and re-cancel.

Notice that Collab will issue out a Cannot Download entry error and the logs will show pointers to uninitialized memory:

Full logs here: https://oc.unity3d.com/index.php/s/ygbrDjaUYtR1tDG

2017-0508 15:30:35 GMT 2539.130019 Collab Error 53161984 994b348af4d7a4ba59d47343ff46ea00 CURL ERROR [DownloadEntryRequestAsync] [Cannot download entry] [] 3617275732.855192s {"target":"Ôæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔ/Assets/Folder002/text000734.txt.meta","fileSize":177,"method":"GET","responseHeaders":[],"uri":"https://collab.cloud.unity3d.com/api/projects/63e2b84a-ef8f-4b90-bdf9-f81f414a2d27/cache/source/ce136e67fffb6831aef980222ed50e17"} [Collab 2017-0508 15:30:35 GMT][Error] 'Cannot download entry' (27) returned in '/Users/pedroa/Development/unity_staging/Editor/Src/Collab/Requests/DownloadRequests.cpp' at line 61
[Collab 2017-0508 15:30:35 GMT] DownloadEntryRequest failed, Reason: 0 Url: https://collab.cloud.unity3d.com/api/projects/63e2b84a-ef8f-4b90-bdf9-f81f414a2d27/cache/source/ce136e67fffb6831aef980222ed50e17 Result:
CreateDirectory '/Users/pedroa/Desktop/Unity folder/CollabIssueVerification_May8th/Ôæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔæ≠fiÔ' failed: File exists (current dir: /Users/pedroa/Desktop/Unity folder/CollabIssueVerification_May8th)
Cannot download entry '/api/projects/63e2b84a-ef8f-4b90-bdf9-f81f414a2d27/cache/source/a63c2a0a9b1ace8d36114aa97448d8a2?name=text000735.txt', unable to create parent directory