Quicken prompted me to update to 8.4.2 this morning from my previous build 8.3.3. Once updated, none of my data files would open including backups from just prior to the update, from December, from November, etc. Support chatbot was unhelpful and gave me false information about reverting back to 8.3.3 (said those build files were not available). A human chat was slightly more productive but also had major issues. The tech repeatedly told me that I wasn't doing the backup/restore process correctly despite my assurances that I was. When I shared my screen with her, it affected my MacBook so that I could not see the list of files to choose one for restoration. We had to turn off the screen share to continue. She then told me repeatedly that my files were corrupted and empty. I knew they weren't and explained again that this was all caused by updating to 8.4.2. I begged for an 8.3.3 build file and she was helpful showing me that they are available on the Quicken site. I deleted 8.4.2, downloaded and installed 8.3.3, and restored my backup from this morning. Looks to be all good! Lost several hours to this mess, but I don't think I lost data. But, you have a major bug somewhere in 8.4.2!!!