Nextcloud version : 20.0.6
Operating system and version : Centos 7
Apache or nginx version (eg, Apache 2.4.25): Apache 2.4
PHP version (eg, 7.4): 7.2
The issue you are facing:
From the web interface, I’d like to modify my office files in MS office 2010 installed on my computer.
From now, I can only open the file in MS Office, modify and save it on my computer. Then, I have to upload it on NC. I’d like to modify it with MS Office “on line”.
I do not have Collabora or Onlyoffice, just MS Office 2010
Is this the first time you’ve seen this error? (Y/N): N
Unfortunately it isn’t possible to edit your Office files online with MS Office 2010 since that is a client program which runs locally on your client OS and is not a server application.
You could mount your NC files as a drive on your computer via webdav. Then local applications can use the files just like they would if stored on your C:\ drive or equivalent.
This wouldn’t be via the web interface but since MS Office is running on your local computer inherently, the web interface wouldn’t necessarily even be relevant.
You have basically three options to edit the files that are stored on your Nextcloud.
Edit them in your browser with either Onlyoffice or Collaboara as @szaimen mentioned.
Connect your Nextcloud via webdav to your computer and use whatever editor that is installed on your computer. e.g. MS-Office, as @jtr mentioned
Download and install the Nextcloud Sync Client on your comuter and use whatever editor is installed on your computer. e.g. MS-Office. That’s what what I do, not with MS Office though