A group of Microsoft Products and technologies used for sharing and managing content, knowledge, and applications.
Hi Nicole Kerr,
I feel sorry the frustration it caused and would like to help.
Before started, I'd explain we suggest our customers post one issue in each thread, so that our support engineers can help to further investigate a specific issue and provide corresponding assistance. This will also benefit community members when they search answers based on the title, let's focus on your first issue that external users can’t see some files sometimes within a specific folder shared with them.
First, you can check if the file is checked out or not. Because when the file is checked out, other users can’t view or edit the files. To check that, you can refer to Check out or check in files in a document library. Or the file needs more time to finish the uploading while user want to access.
Second, you can go to Library Settings-> Versioning Settings-> Draft Item Security,****see which item you checked.
In the meantime, another possible cause can be the specific item permission. Because we can set individual file permission not to inherit its folder permission, and users can only see items they are allowed to access. To check specific item permission, you can select the item > click the “!” icon on the top right of the page > Manage access > Advanced > check permissions > input the specific external user account having the issue > check whether he has the correct permission. If you see “Delete unique permissions” button on the top left of the tool bar, that means this specific item has separate permission from folder permission, which means the item is not inheriting the folder permission.
If the information above doesn’t resolve the problem, please provide us more information below for further investigation:
1. Does the issue affect specific external users or all external users?
2. Does the issue happen to specific files or specific file types? Or does the issue happen to random files?
3. Does the problematic file inherit its folder permission? Does the user have the right permission to the problematic file?
For your second issue that external users can’t upload files with edit permission, I suggest you to check the permission level in the Site Permission->Advanced permissions settings->Permission Levels->Edit to see if “add item” option is unchecked or not. User cannot upload files if “add item” is unchecked.
If my suggestions don’t work, I recommend you can open a new thread and provide error information so that our other members and support engineers can give helpful suggestions to resolve this problem.
Best Regards,
Ivy