I can't find the "tools_r25.2.3-windows.zip" file . All i found was "sdk-tools-windows-3859397.zip".
Please help me, I don't know what to do, my unity is up to date but gives me the error "Unable to list target platforms".

It is FIXED in 5.6.0p4 !!!

I have 5.6.0p3 but still have this error. I also downloaded latest "Android SDK Tools" 26.0.2 and restart everything but still have "Error:Invalid command manifmerger". I see no other choices than try with the 2017.1.0b3 ...

The merge issue is a weird one and I found that it was to do with the way Unity is creating the manifest file in the temp folder.

Try adding this default androidManifest.xml to your project under plugins/Android remembering to change the package name and remove any unwanted permissions. The issue seems to come from there being no manifest file to actually merge with and also (when you do add the manifest) there may then be issues with some manifest files in your project (in the other libs and plugins) using incorrect icon references.

<?xml version="1.0" encoding="UTF-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:installLocation="preferExternal"
package="com.yourpackagenamehere"
android:versionName="2.0"
android:versionCode="2">
<supports-screens android:smallScreens="true" android:normalScreens="true" android:largeScreens="true" android:xlargeScreens="true" android:anyDensity="true" />
<uses-feature android:glEsVersion="0x00020000" />
<uses-sdk android:minSdkVersion="19" android:targetSdkVersion="25" />
<application android:icon="@drawable/app_icon">
<activity android:name="com.unity3d.player.UnityPlayerActivity" android:label="@string/app_name" android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen" android:launchMode="singleTask" android:screenOrientation="landscape">
<meta-data android:name="unityplayer.ForwardNativeEventsToDalvik" android:value="true" />
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.GET_TASKS" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="com.android.vending.CHECK_LICENSE" />
</manifest>

yeah gee thanks unity devs, did you even test the fix before releasing it? I'm starting to think I should ask for a refund for my pro license, I've just spent a whole week working through unity bugs because you guys don't seem to give a toss anymore

I still have the same problem in the latest version of Unity 5.6.0f3 (on windows 10).

This issue is fixed in 2017.1, but what version of Unity is that?
I'm sorry if I don't understand what "Fixed in Unity 2017.1" means, but I guess it means that this issue is fixed in Unity version 2017.1.
But there is no version of Unity called 2017.1, or am I all wrong here?

This is the only version of Unity I can find:
https://unity3d.com/get-unity/download/archive

Anyway, I got the problem (and still have) after updating Android Studio to the latest version 2.3.1, which include the latest version of Android SDK.

In case it helps anyone, I've managed to build around this Manifest error by doing this:

1) after a failed building attempt, go to the Temp/StagingArea folder in your Unity project, grab the AndroidManifest-main.xml file

2) copy it into Assets/Plugins/Android, rename it to AndroidManifest.xml

3) in the file itself, remove "android:theme="@style/UnityThemeSelector" and "android:debuggable="true""

With that, at least I'm able to build for Gear VR.

This is the error I get when building for Gear VR (5.6.0p4):

D:\My-Game\Temp\StagingArea\AndroidManifest-main.xml:4:125-150 Error:
Attribute application@debuggable value=(true) from AndroidManifest-main.xml:4:125-150
is also present at AndroidManifest.xml:3:148-174 value=(false).
Suggestion: add 'tools:replace="android:debuggable"' to <application> element at AndroidManifest-main.xml:4:3-12:17 to override.
D:\My-Game\Temp\StagingArea\AndroidManifest-main.xml:4:16-57 Error:
Attribute application@theme value=(@style/UnityThemeSelector) from AndroidManifest-main.xml:4:16-57
is also present at AndroidManifest.xml:3:83-147 value=(@android:style/Theme.Black.NoTitleBar.Fullscreen).
Suggestion: add 'tools:replace="android:theme"' to <application> element at AndroidManifest-main.xml:4:3-12:17 to override.

UnityEditor.HostView:OnGUI()

Actually I'm still getting this error when building for Gear VR (I don't get it anymore when building for Cardboard)