Generally you can't pin a portable app to the taskbar since the AppID of the launcher is different from the actual app executable, therefore the windows taskbar can not group them into one place.
I found a solution to this problem here:
http://www.neowin.net/forum/topic/985014-guide-pin-programs-with-custom-...
Here is an easier version (I think):
1) Download mkshortcut from here: http://www.mediafire.com/?gzkgthmjhyv
or from the guide above
2) Extract the zip file; you will only need the mkshortcut.exe file inside the release folder.
3) copy mkshortcut.exe to your portable app main directory.
4) (Shift + Right Click) inside the your portable app main directory
Click "Open command window here".(Don't right click on any icons)
5) Type something like the following into the command line window:
mkshortcut.exe -output [Shortcut Name].lnk -target "%cd%\[Program Launcher].exe" -appid "[AppID]"
Where...
Shortcut Name = The name of the shortcut you want to create.
Program Launcher = The portable launcher name (usually ends with the word Portable.exe)
AppID = you can type the application main executable path instead of the ID.(application executable is usually inside the App directory)
Example: for Firefox Portable
mkshortcut.exe -output Firefox.lnk -target "%cd%\FirefoxPortable.exe" -appid "U:\Programs\Internet\Browsers\Firefox\App\Firefox\firefox.exe"
6) Click Enter and a shortcut will be created for you inside the portable app main directory.
7) Drag & Drop the created shortcut to the taskbar to pin it.
and that is it, now you are done.
Extra Tip: When installing a portable app don't put the version number in its path so you wouldn't have to do this every time you update the app.
Note: I know that pinning portable apps is kind of weird, but if you are like me, someone who doesn't like installing all programs every time you re-install windows, then this should be useful.
Following is another way that i found working:
e.g. Copy the FirefoxPortable.exe to c:\TEMP
When i use this trick i get double icons as soon as i open the shortcuts :/
is there a workaround for that?
https://www.dropbox.com/s/65yxh83bn3r42hp/Screenshot%202016-03-02%2014.5...
Thx for the idea - fooling Windows 10 into creating a pinned "firefox" in the tastbar. It almost worked. I dragged Chrome to the taskbar and pinned it. Then I rt-clicked on the icon, then rt-clicked on "Chome" in the context menu, and selected Properties. I edited the name, location, folder - everything including changing the icon. The icon didn't change, but it does start Firefox - maybe I can put up with the silly chrome icon.
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Today I noticed the icon had changed to Firefox overnight while the computer was sleeping. Yay!
You need to right click properties then change icon and point it to place with Firefox icon and since it is the "portable" point it to the icon in the portable program
“Be who you are and say what you feel because those who mind don't matter and those who matter don't mind.” Dr. Seuss
For whatever reasons FirefoxPortable and ThunberbirdPortable require actual hexadecimal AppID for this to work under the latest Windows 10.
Here is how to do it: http://www.neowin.net/forum/topic/985014-guide-pin-programs-with-custom-...