Unity collaborate circulation sync error

Now have used collaborate with other team members back and forth for 1 week,

1) first sync button appears,

2) after press sync button, warning pop up appears,



3) click yes, then suddenly it download whole project files (7.5gb) total,

4) after that, sync errors appear,





for see red files, if click View or UseMerge button, then this error appears,





I am using Winmerge tools, even after deleting collab.snapshot, errors.

How to solve this?

Thanks.