Have to admit I don't understand this but today of the many hundreds of times I have opened a .jpg file in PhotoShop Elements 2, Avast thinks it may be unsafe although it cannot fond enough evidence to ID it as malware and recommends action to Open in Sandbox. I have scanned with Avast and Malwarebytes the Adobe folder with no issues. For the time being I have said OK to it opening in the Sandbox. It does so, analyses then closes the program so I can't run it unless I say 'Open Normally'.
Why should it do this now after all this time?