While I was trying to Update my Project I was making - I got an error for the first time I\'ve seen:
\'An error occurred while signing: SignTool.exe n
You can fix this by clicking on installation application of VS. Then click Modify > Mark ClickOnce App and then upgrade your VS. Also i think @Alex Erygin is right. It is a bad solution to Click Once application --> Properties --> Signing -> Uncheck Sign the ClickOnce manifests. This is not a solution. It only circumambulated the problem.
Click "Project" at the top. Then click " Properties" -> Signing -> Unchecked [Sign the ClickOnce manifests] is now working
This is a simple fix. Open the project you are getting this error on. Click "Project" at the top. Then click " Properties" ( Will be the name of the opened project) then click "Security" then uncheck "Enable ClickOnce security settings."
That should fix everything.
ClickOnce Publishing Tools are not installed as part of the Typical Installation Options. So you have to install it in advanced mode.
This dialog can be found in Windows 7 by going to Control Panel > Uninstall a program, right-clicking on Microsoft Visual Studio Professional 2015 and selecting Change. A Visual Studio dialog will open up. Select Modify from the set of buttons at the bottom and the above dialog will appear.
I needed Signing hence couldn't un-check as suggested.
Then goto Control Panel -> Programs and Features -> Microsoft Visual Studio 2015 Click Change then the installer will load and you need to click Modify to add ClickOnce Publishing Tools feature.
Windows 10 users can find signtool.exe in C:\Program Files (x86)\Windows Kits\10\bin\10.0.18362.0\x64 folder (10.0.18362.0 in my case, or other version).
But first, make sure you've installed Windows 10 SDK
Then, check Windows SDK Signing Tools for Desktop Apps is installed by going to Control Panel > Programs > Programs and Features, choose Windows Software Development Kit - Windows 10.0.18362.1 (in my case, you version may be different), right-click, choose Change, choose options Change then click Next.