I can't get SupportAssist to install but, "Dell Command Update", works perfectly.  Get it from here:  https://www.dell.com/support/home/en-us/drivers/DriversDetails?driverId=601KT

Hi babe13:

What is the edition (e.g., Home, Pro, etc.), version and OS build number of your Win 10 OS shown at Settings | System | About | Windows Specifications? If you open a Run dialog box (Windows key + R) and enter msinfo32 to open the System Information panel, what is your current BIOS version (look in the field titled "BIOS Date/Version")? What version of Dell SupportAssist is shown at Control Panel | Programs | Programs and Features?

When you say that SupportAssist worked correctly before the Windows update, do you mean that your laptop shipped from the factory with an earlier version of Windows and that you've recently upgraded to Win 10, or do you mean that you've had a Win 10 OS for a long time and that SupportAssist stopped working after your October 2022 Patch Tuesday updates were delivered on or around 11-Oct-2022?

Just an FYI that the Inspiron 5559 support page at https://www.dell.com/support/home/en-ca/product-support/product/inspiron-15-5559-laptop/drivers recommends Dell Update Application for Windows 10 v4.2.1 (Dell-Update-Application-for-Windows-10_YGN8R_WIN_4.2.1_A00.EXE, rel. 04-Jun-2021) for a 64-bit Win 10 OS. I'm not sure why Dell doesn't recommend the latest Dell Update v4.6.0 for your computer model (I confirmed the Inspiron 5559 is not listed <here> as a compatible system for v4.6.0), but I also noticed that the last BIOS update released for the Inspiron 5559 was Dell Inspiron 5459/5559/5759 System BIOS v1.9.0 (rel. 02-Nov-2020). Perhaps you are unable to install the latest Dell Update and/or SupportAssist versions because they don't function correctly with your older BIOS.

I don't know if it's relevant to your problem, but LaurentGrenet posted 13-Oct-2022 in Unable to Update Dell SupportAssist to Latest Rev that MS .NET Runtime v6.0.10 (rel. 11-Oct-2022) was already installed on their system when they tried to update to the latest SupportAssist v3.12.3.5, and the SupportAssist installer logged an error because it tried to install an older .NET Runtime v6.0.9 ("Error 0x80070666: Cannot install a product when a newer version is installed"). I have no idea why the SupportAssist v3.12.3.5 installer would not be smart enough to simply skip over the installation of .NET Runtime v6.0.9 when it finds a newer v6.0.10 is already installed, but if LaurentGrenent's assumption is correct and that is the reason why they can't update to SupportAssist v3.12.3.5 then perhaps your current MS .NET Runtime v6.0.10 is causing the same issue.
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64-bit Win 10 Pro v21H2 build 19044.2130 * Firefox v105.0.3 * Microsoft Defender v4.18.2209.7-1.1.19600.3 * Malwarebytes Premium v4.5.15.215-1.0.1784 * Macrium Reflect Free v8.0.6979 * Dell SupportAssist v3.12.3.5 * Dell Update Windows Universal v4.6.0 * Inspiron 5583/5584 BIOS v1.21.0
Dell Inspiron 15 5584, Intel i5-8265U CPU, 8 GB RAM, 256 GB Toshiba KBG40ZNS256G NVMe SSD, Intel UHD Graphics 620

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@lmacri wrote:
...I don't know if it's relevant to your problem, but LaurentGrenet posted 13-Oct-2022 in Unable to Update Dell SupportAssist to Latest Rev that MS .NET Runtime v6.0.10 (rel. 11-Oct-2022) was already installed on their system when they tried to update to the latest SupportAssist v3.12.3.5, and the SupportAssist installer logged an error because it tried to install an older .NET Runtime v6.0.9 (" Error 0x80070666: Cannot install a product when a newer version is installed"). I have no idea why the SupportAssist v3.12.3.5 installer would not be smart enough to simply skip over the installation of .NET Runtime v6.0.9 when it finds a newer v6.0.10 is already installed, but if LaurentGrenent's assumption is correct and that is the reason why they can't update to SupportAssist v3.12.3.5 then perhaps your current MS .NET Runtime v6.0.10 is causing the same issue.

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Hi babe13:

Have you made any progress trying to install SupportAssist v3.12.3.5 on your Inspiron 5559 / Win 10 / MS .NET Runtime v6.0.10 machine?

Note that Dell employee DELL-Nathalia M just posted step-by-step instructions for installing SupportAssist v3.12.3.5 in Admiral1989's SupportAssist - Installation Failed Message on 18-Oct-2022.  These instructions advise that users begin by removing all traces of previous SupportAssist installations using the Microsoft Install and Uninstall troubleshooter.

DELL-Nathalia M's instructions were revised shortly after posting and they now advise that any user with MS .NET Runtime v6.0.10 (rel. 11-Oct-2022) should also uninstall that program from Control Panel | Programs | Programs and Features and then install the older MS .NET Runtime v6.0.9 before trying to install SupportAssist v3.12.3.5. That implies that Dell believes LaurentGrenet's claim that the current SupportAssist v3.12.3.5 installer is not smart enough skip over the installation of .NET Runtime v6.0.9 (see the minimum system requirements for SupportAssist v3.12.3 <here>) when it finds a newer v6.0.10 is already installed.
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64-bit Win 10 Pro v21H2 build 19044.2130 * Firefox v106.0.0 * Microsoft Defender v4.18.2209.7-1.1.19700.3 * Malwarebytes Premium v4.5.15.215-1.0.1784 * Macrium Reflect Free v8.0.6979 * Dell SupportAssist v3.12.3.5 * Dell Update Windows Universal v4.6.0
Dell Inspiron 15 5584, Intel i5-8265U CPU, 8 GB RAM, 256 GB Toshiba KBG40ZNS256G NVMe SSD, Intel UHD Graphics 620