When I try to move picture(s) from Lr 6 to Ps 2021 there is a problem. I also had this problem going from Lr 6 to Ps 15. I am running Win 10. I select the pictures in Lr I want to edit in Ps by using Lr I go to Photo>Edit In>Edit In Photoshop Elements Editor (or Open in Layers in Photoshop). Photoshop Elements Editor will open (or pop up if already open). But the pictures do not appear in Ps Editor. After a few minutes, I will get the error message in Lr: "The files could not be edited because Ps Editor could not be launched (even though it was launched). It doesn't matter if I use the top menu in Lr or right click on the pictures in Library and choose the same choices.
Thanks for the detailed response. Could you please mention the exact version of Windows 10? Also, please share the images with me via personal message.
Edition Windows 10 Home
Installed on 8/8/2020
OS build 19042.572
Experience Windows Feature Experience Pack 120.2212.31.0
This reply mode does not allow me to attach a picture file. I can say, these are either RAW (.CR2) or .jpeg files and none move to Ps without the process I described above.
Thanks again for your time.
Can you try clicking on the icon highlighted in the screenshot below to upload the picture? Or you could also upload the pictures to Google drive/One drive and share the link with me via personal message.