"Please be informed that, the Cloud Drive desktop application is no longer available for download from the Amazon.com website. However, if you currently have the application installed on your computer it will continue to upload files, photos, and videos to your Cloud Drive account. If you uninstall the application, you won't be able to reinstall it from the website. I'm sorry for any inconvenience caused."
"Alternatively, you can access your Cloud Drive from any web browser. You can upload files, photos, and videos to your Cloud Drive account on the website at any time"
"You can use the "Select Photos and Videos" button that displays onscreen to choose multiple files to upload at once. Uploading folders is not currently available within the Cloud Drive website."
"I'm really sorry for any inconvenience this may have caused. "
"Your concern will be reviewed for consideration as we will make every effort to evaluate the information you have provided, and try our level best to lead it to program changes or enhancements."
My copy of ACD sync pegs my upload meter ~80% of the time even when it has been hours to days since I last touched a file in its folder. If this bug is widespread, it might make sense for them to pull the buggy app until they can get an update ready, even though the issue isn't particularly worrisome or pressing. They would just rather not have angry customers and high bandwidth costs.
Edit: before the post title was edited, it suggested that all of Cloud Drive was being discontinued.
