Thank you. I am certainly not suggesting that Adobe's software is not working as intended or that anyone needs to look into anything... I'm only seeking to understand why clicking on an Adobe file saved in jpg format a month, a year, five years ago now doesn't work any longer. I have never knowingly used any other app (although I can see that the 'rogue' files will open in WMP) : they have always opened immediately, apparently as Adobe files (although I believe you when you tell me they are not!) You are unquestionably correct that the pop-up box, which only started appearing since this became a problem, indicates there is a 'mistake' : what I'd like to understand is where the problem lies and how to correct it. Clearly something has changed and I will have to, as you advised initially, figure out what it is. I have never used Photoshop, however that suggestion lit up the thought that it may be something connected with a new Canon printer, installed recently, and coinciding with this issue, which has a piece of unwanted Canon software which has kept popping up, PictureGarden or something... could that have an influence or am I barking up the wrong tree?!
... View more