What version of Aquasuite were you using before you updated to X.87? D5 Next firmware version 1025 was released with Aquasuite X.78. D5 Next firmware version 1026 was released with Aquasuite X.85. You are trying to jump from firmware version 1025 to firmware version 1027, skipping version 1026. I don't know if this could cause the problem you are having, but maybe. Hopefully someone from Aquacomputer will chime in here. If there was a problem with the D5 Next version1027 firmware, there would be lots of posts about it in this forum, and there aren't, so it must be something specific to your situation. Have you tried a full power down, PSU off, unplug power cord, wait 5 minutes (or push the Start button to drain any residual charge), then rebooting?

For what its worth, last night I updated my rig with a D5 Next from AQS X.85 to X.87, skipping X.86. That worked fine and the D5 Next firmware update to v1027 also worked fine. I always feel some apprehension whenever I update AQS and more so when a firmware update is included. I have encountered some strange bugs in AQS, but I have never had a problem updating AQS or device firmware I have also never skipped a firmware version.

I did ask Google AI (Gemini) about your problem. It said that jumping past D5 Next firmware version 1026 could cause your problem. It suggested checking the Windows Event Viewer for Error ID 0x8004 or 0x8007, which both indicate a USB access problem. It also said that firmware version 1026 changed the way the device presents itself to the Windows USB stack. By trying to jump from 1025 to 1027, the D5 Next is likely trying to use an old "communication language" while the new X.87 software is expecting the "1026/1027" language. It claims there is a "Repair Firmware" or "Firmware Recovery" button in the Aquasuite Service tab that will force the new firmware to load. It also suggested looking in Device Manager for "Aqua Computer Bootloader" or an Unknown Device (Yellow exclamation point). If you see either of these, right-click on it and select Uninstall. Then remove power from the D5 Next and plug it back in. This forces Windows to re-enumerate the device which may cause the installer to attempt the firmware flash again. Another option is connect the D5 Next to another Windows computer that is running an Aquasuite version that is lower than X.85, then let it update to X.85 which will also install D5 Next firmware 1026. Once the D5 Next is updated to firmware version 1026, connect it back to the first computer. Aquasuite will see it and offer the update to version 1027.

I don't know if any of this will work but its worth checking. If none of the above gets you anywhere, I recommend contacting Aquacomputer Support. They do post in this forum but there is no guarantee of that. This is more of a Community Forum, not a Support Forum. Aquacomputer does have an "Official Support" subReddit under r/Watercooling. I have personally had better luck getting a response from them there than here, but the most direct way is to send Aquacomputer support an email. support@aqua-computer.de Aquacomputer Offical SubReddit