winstore.app.exe is a application which is most likely legit. So, if winstore.app.exe is on your system, it is most likely ok, and will NOT be a cause for concern. Even if your system is clean, it is still recommended to run a good antivirus with a good track record, in order to yourself your PC against threats.
Normally, this application is located in C:\Program Files\WindowsApps\Microsoft.WindowsStore_11706.1001.26.0_x64__8wekyb3d8bbwe\WinStore.App.exe.
The MD5 checksum for this file is cdca45d2cba81f3057e728c873dc466a.
This program is NOT registered as a Windows service. This is very good.
This executable uses the net to communicate. Today this is expected from a program. For example, most of the programs on your computer check for updates. In order to do this, Internet communications are necessary.
This is a 64-bit executable. It runs using the full capacity of modern CPUs.
The description stored in the program is Store.
File version extracted from the file 11706.1001.26.0.
Company name Microsoft Corporation.
Legal copyright notice Copyright © 2015.
winstore.app.exe appears to have a visible user interface. This means it doesn't operate in a kind of stealth mode. Its activity is clearly displayed to the user.
The digital certificate is missing from this program. The authors did not bother to sign it. This is probably bad.
This application does NOT have an uninstall routine stored in registry.