Outlook issue referencing mapped Sharepoint library

[CharlesBetman]

At our company we are using Microsoft 365 Business Standard. On premise we have a NAS with several drives (our local fileserver) and are thinking about migrating the data to Sharepoint. We wish to keep using mapped Sharepoint libraries in Windows Explorer.

So as an experiment I have uploaded the data on our NAS Q:-drive to a Sharepoint library, and mapped it to drive X: (doing all the neccesary stuff like adding Sharepoint as a safe website using Internet Explorer). Both drives, Q: and X:, are accessible with Windows Explorer, Sharepoint somewhat slower than the NAS, but so far so good ...

However, problems occur with the locally installed Outlook trying to access the mapped Sharepoint-library by selecting the X:-drive in order to handle an attachment. When trying to attach a document to an email Outlook is very slow, and I mean very slow, accessing the mapped library.

Also to select the destination folder in order to save an attached document to the X:-drive does take a lot patience, as well as hitting the save-button. Even worse, although it looks like Outlook finally saves the attached document, the document cannot be found in the Sharepoint library (not browsing Sharepoint online itself, and not in Windows Explorer). Saving the file didn't succeed, but no message is presented.

Our desktops and laptops are running Windows 10 Pro and are up-to-date.

Anyone who experienced the same problem with Outlook accessing mapped Sharepoint libraries? A configuration issue for some of our devices perhaps? I hope somebody can help me with this one. 

[#2]

In addition I created a new document in Word and Excel, tried to save the document to a mapped Sharepoint library, and the same problem occurred. Slow access to the folder, and an error saving the document: "An error has occurred with your permission to the network or file.".
However, saving the document selecting the Sharepoint - Sites option in Word or Excel works fine, so I assume it's not an authorization issue.

[#3]

I also posted my question in de Microsoft Community: https://answers.microsoft.com/en-us/msoffice/forum/all/outlook-and-also-word-excel-issue-referencing... 

The suggestion was to have a look at syncing SharePoint files with the new OneDrive sync client

First, I want to explain that mapping the SharePoint library to a network drive uses WebDav, an older technology which is slower and less reliable than syncing SharePoint files with the new OneDrive sync client. The OneDrive sync client provides Files On-Demand, which allows you to access all your files in OneDrive without using local storage space.

I did and that seems to be a good alternative for using WebDAV. I'm planning a PoC with several users and will be back sharing the results.