I have an update on this...
I noticed sometimes that as soon as I opened Photoshop, if I clicked on Help immediately I would see the "Welcome..." option, then a second or 2 later "Welcome..." would disappear from under Help.
So once I clicked on "Welcome..." as soon as Photoshop opened and the Welcome screen opened as I would expect it should.
Next I closed PS, when it launched I tried to click on "Welcome..." again. I saw it under Help, clicked on it, but this time and all subsequent times, it gives me an error that the Welcome screen is not installed.
Also I have reset my preferences several times, but that doesn't fix it.
Pls see my last comment.
I do not have a "Welcome..." option under Help to click on. I did see that option immediately after PS launches but then it goes away after only a sec or 2. in most cases when I click on it I get an error.
Uninstalling and re-installing didn't fix it, neither did turning off my anti-virus software. I had read somewhere that AV software could cause a prob.
Obviously its not a major issue, but it is highly annoying and would like to know what is causing it and how to fix it.
I believe you have an installation problem. Others have had problems with the Welcome Screen and I had a problem after the 15.2.2 update. Others were not able to Play the video tutorials from the welcome window. Photoshop seems to use CEPHtmlEngine.exe to display the Welcome screen. The CC 2014.2.2 update installed on my machine without a problem. CC 2014 worked and I had turned off the welcome screen. However I did not have the new Photoshop CC 2014 preference Do not show Welcome Screen on launch and when I tried to use menu Help>Welcome I received a popup error stating Photoshop could not start the plug-in because it was not signed. The way I was able to fix this problem was to download the direct CC 2014 installer and install CC 2014 on top of the CC 2014 currently insall. CC 2014 installed and was installed activated and after I used menu Help>Update to get CC 2014 up to CC 2014.2.2 all worked my Add-ons and preferences were still there. However if I start CC 2014 and immediately try to open the Welcome screen I will get the pop-up your getting Welcome Dialog not installed. But when I click OK and try menu Help>Welcome a second time it works. The new Preference Do not show Welcome Scree on launch is there and I can set it there or from the welcome screen option.
Just found this on Adobe Troubleshoot Welcome Screen
We know its HTML based so things that effect browsers may also affect this feature clearing Photoshop things like recently opened files perhaps caches like the bridge and ACR have resetting tools and Photoshop preferences may also help get Welcome working.
Adobe has a Problem with this feature the existence of the above link shows your not alone.
At the bottom of their trouble guide there is a script to turn it off
// Thu Oct 30 2014 14:08:39 GMT-0700 (Pacific Daylight Time)
// Enable or disable the hello/welcome screen by setting the flag in the Photoshop registry
var desc = new ActionDescriptor();
desc.putBoolean( stringIDToTypeID( "show" ), false );
app.putCustomOptions( "0685b2e9-19db-4679-90b9-34644fcc7884", desc, true );
alert("Hello will not appear the next time you launch Photoshop.");