Files shared with a link
Google Drive files that are shared with a link will be copied, but will lose the share link. You will need to share the file in SharePoint once the file is migrated. For more information, click here.
Some migrated files are not exactly like in Google Drive
It is possible that some files will not look exactly like in Google Drive. When we download file from Google Drive to your SharePoint site, we use the export function. The export function converts a file from Google Drive format to Office format. This export function is not perfect and can make the migrated file look slightly different. This will only happen to some files that are in Google format since we have to use Google to transform them.
Migrating shared files and folders
When you are migrating to something other than OneDrive for Business, the files that are shared at the source will have a different behaviour at the destination. Instead of sharing the file, we will apply a set of permissions that will allow access to people with which the content was shared. They will not find the files within their folders or in a "Shared with me" view, but they will have access to the files if they go to the location where they were migrated. If you want the files to be easily found by users in their "Shared with me" view, the best way to achieve it is to migrate to OneDrive for Business.
Also, to prevent duplicating files, you should always migrate using the "My Documents" view (which is the default view) when migrating multiple users' files. This will only copy the files if the user is the owner of the file. For example, let's say you copy the files for users A and B to OneDrive for Business and user A has shared a file with user B. Since user A is the owner of the file, it will be copied into his OneDrive for Business and it will be shared with user B so that it appears under his "Shared with me" view in OneDrive for Business. However, if you use the "Shared with me" or "All Documents" view to perform the migration in Sharegate, then the file will also be copied into user B' OneDrive for Business, which will create a duplicate. This is a problem since the changes made to one file will not be reflected into the other one. These views allow you to copy files even if the user is not the owner, which can be useful in some scenarios, but you have to be careful in order to avoid creating duplicates.