time for a look at causes a bit. Lots of complaints. No answers. this is a Dev to Dev forum. I doubt Apple has much interest in our complaints here. I’ve narrowed this down a bit. I do a lot of large scale file movement. Be it transferring drive to drive or renaming batches, in the hundreds or thousands of files at a time. opening and modifying multi-gigabyte documents (PDF et al). Other enormous file system tasks (compression, decompression etc). there is something wrong with the file system handling. It’s that simple. maybe some other users with different setups can help me track this down? 2017 27” iMac core 5. 64gig ram available. 256GB main drive. 22 external drives. Range 512GB-8TB. All but one are SSDs. all drives APFS All non-system data is on external disk. booting with my externals off Takes about 20-30 seconds. Not bad. Booting with them turned on is understandably slow and that’s always been an issue. So I’ll focus on post boot. finder has no issues with the onboard disk. Probably because I’ve done nothing to it mod wise and don’t store any external data on it. I Symd documents to an external. some of my more full but lesser quantity disks have no issue either. loading up a folder with a few thousand files in it sparks a spinner. :( regardless of the number of files attempting a batch rename causes major delays and occasionally crashes. I’ve had it as minor as the app crashing to finder restarting to a whole system crash. (I use ReBamer and NameChanger mainly but also A->B and the cl tool rn.) ingesting more than 100-150 files causes a freeze. System may or may not overcome it. Actually changing more than a handful of file names also crashes. finally in batch transactions such as a replace action, (eg rn . = [space] or rn _ = -) it locks up after about 50 reads, regardless of number of changes. file count heavy actions such as loading Acrobat CC and a portfolio causes a hang. looking through multiple threads about the slowdown and my own experiences, most lead me to believe this is a file system issue. slow boot on a single drive or a hang on a 1500 file directory equate to the same thing given other similar freezes. did apple change APFS with the pre-R beta to the post-r betas? I’ce tried rebuilding spotlight and repairing file maps. Both fix issues for a brief time; a few minutes to a few hours. I’ve also tried dual booting a clean BS 1b2. Boots and runs fine. Until I access an external drive. Then the same freezes. my drives are fine. According to MacOS, SMART, and manufacture tools when testing them through a live boot, not on my iMac and on a laptop. my RAM is fine. So says a live boot of MemTest. that leaves the software being the issue in my book. Anyone here have file system experience? I’d be happy to supply logs. Both from MacOS and diagnostics from the drive manufacturer’s tools. I know it’s not actual corruption. My data is fine and the APFS read driver for Windows let’s me read everything on my drives. so there’s some disconnect between the drive supplying the table/tree/data etc and Big Sur actually understanding it.

@ javasol Did you move admin to admin or user to admin in the new profile? if this works it would be far easier than a full dress install. I figure I’ll loose custom shortcuts and bindings. aside from that anything else loss in a new account? You mentioned needing to migrate to a new user and I’m wondering just how much would be involved. granted I could probably just do it and see. I can always delete user 2 and go back. but I’m trying to decide which would be the quicker solution. Like you, migrate nearly 4 years of settings, or find and fix the file system issue. I've hit a wall with user-land fixes for the FS.

BTW: on Ventura it's Desktop & Dock scroll down to :Hot Corners... bottom of the tab.