Issue installing application on Garmin Forerunner 955

You still do that, but it's a bit more complicated. What OS is on your computer? Do you see the files on the watch?

If you are using macOS, you need a 3rd party app like OpenMTP to manage files on most newer Garmin devices: https://openmtp.ganeshrvel.com/ 

If you are using Windows, you can use File Explorer to manage files, same as on older devices (albeit with a few limitations, like not being able to directly create or open files on the device). (e.g. if you want to create a .txt log file to go with your app, you have to create it on a different drive and copy it to the device; you can no longer create such a file directly on the device from file explorer).

In both cases, you copy the app PRG to the \GARMIN\APPS folder.

EDIT: either way, you must completely close Garmin Express before attempting to access files on the device. (Including closing the Garmin icon in the Windows notification tray or macOS menu bar.)

Thank you for the reply.

In both systems, if I copy my app into the folder, I still can’t see it on the watch.
I tried creating a Public subfolder inside GARMIN/Apps, but the result didn’t change.

In which menu on the watch should I see it?
From the main menu → start → scroll down → add → applications?

my file manifest:

<?xml version="1.0"?>

<iq:manifest version="3" xmlns:iq="http://www.garmin.com/xml/connectiq">
<iq:application id="28241861-f84e-4010-9112-682f50f8587f" type="watch-app" name="@Strings.AppName" entry="SoftTimerApp" launcherIcon="@Drawables.LauncherIcon" minApiLevel="1.4.0">
<iq:products>
<iq:product id="fr955"/>
</iq:products>
<iq:permissions/>
<iq:languages>
<iq:language>ita</iq:language>
</iq:languages>

<iq:barrels/>
</iq:application>
</iq:manifest>

9793217 said:

In both systems, if I copy my app into the folder, I still can’t see it on the watch.

Hmm that's strange.

Note that it's normal for the PRG to disappear from the "file system" after copying it though.

That's because newer watches will immediately "hide" (move to user-inaccessible storage) any PRGs that are copied to \GARMIN\APPS or installed from the store.

The fact that the PRG is no longer visible doesn't mean that installation failed.

9793217 said:

From the main menu → start → scroll down → add → applications?

As it's a device app, the answer is pretty much yes - it should be in the activities/apps list accessible by pressing START from the watch face. Either it should already be in the list, or you should be able to add it as you described.

Take a look at \GARMIN\APPS\LOGS\CIQ_LOG.YML. Is there an error similar to "signature check failed"? That could indicate that app installation failed.

Maybe you have too many CIQ apps installed on the device already? The limit is something low like 20. You can check the limit and the current number of apps installed using the Connect IQ store app on your phone.