I have created a Zap to save files from a Slack channel to a Shared Drive in Google Drive. When I specify a folder to save in in the Shared Drive, the files save there. But when I only select the Shared Drive and don't specify a folder, it saves to My Drive instead. I have also tried choosing Custom for the folder field and typing in root, but it still saves to My Drive. I am the Manager of the Shared Drive (and the only user with access for now).
Here is how it’s configured:
Hi
Help links for using GDrive in Zaps: https://zapier.com/apps/google-drive/integrations#help
TIP: Click the field labels to see tooltips with more info.
Basic answer is the shared Google Drive doesn’t have its own root folder, it is the My Drive folder for each user that acts as the root folder (for each individual)
I think the answer is to create a Folder in the shared Drive and call it ROOT. Files stored in my drive are controlled by the individual even if they are shared in the shared Drive. Files located in the Shared Drive are managed by the Shared Drive.
I suspected this was this case, so I go this Google search response also.
A single user is the owner of files in their My Drive, whereas a group or organization owns files in a shared drive. Each user has a "root" folder called "My Drive" that functions as their primary hierarchy, and consists of everything that descends from this root folder. The user is the primary owner of this folder.
Hi
I just came across your post here and wanted to check in here to see how you’re getting on. Were you able to checkout Troy and
Please do let us know if you’re still in need of some help on this at all - happy to assist further! 
Basic answer is the shared Google Drive doesn’t have its own root folder, it is the My Drive folder for each user that acts as the root folder (for each individual)
I think the answer is to create a Folder in the shared Drive and call it ROOT. Files stored in my drive are controlled by the individual even if they are shared in the shared Drive. Files located in the Shared Drive are managed by the Shared Drive.
Maybe I am using the wrong terminology around “root.” I would like these files to be stored in the Shared Drive and owned by the Shared Drive. I would not like them to be in any subfolder of the shared drive, including one called “ROOT.”
In Google Drive, I can create a new file in the Shared Drive that is not in any subfolder. This new file does not appear in My Drive. It only appears in the Shared Drive.
When I target the Shared Drive with my Zap and don’t specify a folder, the files save to My Drive instead. They don’t end up in the Shared Drive at all. When I specify a folder within the Shared Drive in my Zap, the files correctly end up in that folder, and (again, correctly) do not appear in My Drive.
Interestingly, in the “Data out” inspector for the Test for this step, when a folder is mapped, there is a “Drive Id” value that corresponds to the ID of the Google Shared Drive. When the folder field is unmapped, there is no such field.
I suspect that there is a bug on Zapier’s end in the “Upload File in Google Drive” Zap step that doesn’t pass the Drive Id value to Google Drive when a folder is not specified. I suspect that Google Drive just saves the file in the default location (My Drive) when Drive Id is not set in the API call.
According to Support this is a known bug.
Thank you for looping back with an update here
If you have any other questions, please don’t hesitate to reach out to the Community. We’re always happy to help! 
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.