Thanks for your response. Currently running Windows 10 64 bit with the latest version of PS CC (v 21.2.4). Laptop is Acer Nitro 5 (Intel(R) Core(TM) i5-8300H CPU@ 2.30Ghz 2.3) 32.GBRAM. Interestingly, it now only seems to be a problem if I load PS from CC Desktop. If I load Lightroom from my desktop and then edit an image in PS via Lightroom, then Windows Explorer isn't affected. Well at least it wasn't the last time I Tried it!