Its a bit tricky, but possible :)
When you download the "IP Camera Plugin Installer", klick on it with the right mouse to look inside the app.
(Sorry, but i use a german MacOS and don't know how exactly how it call in english).
go then in this way contents - MacOS. then start the terminal (Harddisk - applications - utilities).
type into the terminal "su" for the superuser rights and then drag and drop the black icon "IP Camera Plugin Installer" from the MacOS Folder into the terminal window.
answer about the password and thats it :)
at the moment my MacOS 10.12.2 Beat (16C53a) without problems.

kind regards
andy

Dear Andy,

Thxn 4 the tip. It got me a bit further. but the install keeps sending ' quit all browsers' even though none are running. Did a restart and tried again, with no succes unfortunately.
You're running a beta version? I'm stil at 10.12.1 :-(.

Many thxn gr Joep

You see its running on my side. I use two cams without a problem.
My MacOS is Version 10.12.2 Beta (16C53a) and Safari Version 10.0.2 (12602.3.12)

Thxn for the post Andy,

Upgrade to the 10.12.2 beta, unfortunately i keep getting the same error " quit all browsers", while none are running. Also turned of auto-pilot from bitdefender with no succes.
Guess i have to wait for an update from tplink. Fortunately i could connect to the camera by direct ip and activate a sound trigger.

Danke schön :-)

Loeschl, I followed your steps perfectly and I am getting the exact same issue as joepwillemsen.

Can anyone help here? Without being able to set up motion detection, the product is useless to me.

Here a Screenshot and it did still work on my Sierra 10.12.4 BETA (16E163f)
I will explain it once again.
1.) Mount the "mac_plugins-2.8.3.dmg"
2.) Don't run the installer, cause its not compatible !
3.) Click with the right Mouse on the "Installer" and use "Show Package Contents".
4.) Open Folder "Contents", "MacOS". There you will finde a black Icon with "IP Camera Plugin Installer"
5.) Now open the "Terminal" from Harrdisk - Applications - Utilities.
6.) Write into the Terminal SU and Drag'n Drop the "IP Camera Plugin Installer" after the "SU " letters.
7.) Press "Enter" and you must confirm it with your Password.

Thats it.
See it on the Screenshot.

Dear Garry,

I fixed the problem in another way, see below:
"
Dear all,

With some workaround i finally was able to instal the plugin on OS Sierra ( 10.12.3 Beta (16D17a)). On my system, the installer would not install ( even with SU-rights manually in terminal), it kept saying browsers were running, even after a safe boot.

I was able to install the plugin manually, by using "show package contents", of the IP camera installer plugin.app , and under "resources" copying the TPcameraplugin.bundle and the TPIPcamH264plugin.bunde, into the internet plugin folder of the user account. After this, rename them, by replacing ".bundle" to ".plugin", and select "use .plugin" in the prompted finder pop-up.

The plugins now appear in in safari plugin preferences, just check the box to allow them running, and you're good to go.

Kind regards,

Joep, the netherlands
"

Bought an NC250 today and had this problem and it was really beginning to do my head in... after stumbling across this thread, I tried the SU ( super user ) option and it just kept saying sorry.
I then just dragged and dropped the file into terminal without first typing SU and it asked me to install, I clicked yes and low and behold, its worked!!

Hope this helps anyone in the same situation.