Hi HannahOrr,
To clarify the situation, I’d like to confirm the following information:
1. Which version of Office for Mac do you use? Is it Office 2011 for Mac?
2. Is it the latest version of Microsoft Document Connection? If not, it is possible to open Excel or Word 2011, click the Help link in the top menu bar, and then choose Check for Updates. This will see if there are any updates for Office 2011, and include any for Microsoft Document Connection.
3. Does your version of Mac OS has the latest updates?
4. Considering “I am able to connect and see all my documents but I cannot open them to edit them using any Microsoft product”, do you mean you cannot click the “Edit” button to edit the selected file?
5. If Document Connection can't figure out what application to open a file with, will you be prompted to select the appropriate application?
6. Can you provide us with more detailed information about the “I can open them using the Mac equivalent but then it won't sync.” to clarify the situation? Do you mean the items cannot be saved directly to OneDrive for Business through Document Connection and newly created files on the Mac need to be stored locally and then uploaded to the system?
7. Does the issue persist on any other Macs using acount?
If there is any error message, you can post screenshots in our forum by clicking Use rich formatting and selecting the Insert Image icon.
Thanks,
Mills Fan