I have experienced the drastic slowdown in completion of Windows updates on a system which did not and never had used WDE. The Windows 10 version was Windows 10 Professional (on a Lenovo X260 with the Lenovo Preload and all patches through February). Lenovo X260 with Windows 10 Pro This system was new in December. It had Symantec Encryption Desktop 10.4.0 with no MP. The system never had WDE. It accepted the January and February Windows Updates for the OS and Office 2016 with no problem. When the March patches hit, it stopped updating at 73%. Since it was inconceivable that the system would finish updating in about a day, I stopped it, loaded an Acronis True Image disk image from just after the February updates and tried the March updates again. The same thing occurred when the March updates hit again. I then reloaded a disk image from before the February updates in case something about the February updates had wreaked havoc with the system. The same thing (stopped at 72%) happened again when the March cumulative update hit. I then reloaded the Lenovo Windows 10 Pro factory preload and all applications except Symantec Desktop Encryption and ran all MS updates up through the March updates. All updates ran correctly. I then installed Symantec Encryption Desktop 10.4.0 with no MP on the fully-updated system. I did not encrypt the disk. When the April 10 updates hit, the same thing happened again--the updating slowed to imperceptible at 72%. Since I had read other posts on this forum, I let the update continue--it took 18 hours, but completed. From this series of events, it seems to me that something about the MS March updates for Windows 10 Pro or Office 2016 broke (and braked severely] if Symantec Encryption Desktop was installed on the system even without WDE. The previous updates through February did not cause the problem, and the March update did not cause the problem if SED was not installed on the same system. Strangely, I haven't experienced any problems with any MS updates through April on my X1 Yoga (with NvME) and Windows 10 Ent and SED 10.4.0 installed even though the NvME disk is fully encrypted. The X1 Yoga has a MP that I got from Symantec before MP1 was released as a trial to see whether WDE would work with the NvME drive. I would very much appreciate any suggestions anyone can provide to keep this from happening again on this X260.