Why cheap USB Serial adapters does NOT work well.

The Short Explanation.
Many low-cost USB to Serial adapters does not work well with newer operating systems such as Windows 11 or even Windows 10. These adapters are made with a low-cost processor chip meeting only a minimum of the industry's standard requirements. The physical quality of the chip is usually fine however the drivers for the chipset are often poorly written programs which makes the adapter unstable and unreliable and not fully compatible with Windows 8 and other current operating systems. Because of this you will in most cases be unable to make a low-cost adapter work well with Windows 11 / Windows 10, especially the 64-bit versions, and you can expect some of the following typical errors:

GOOD

BETTER

BEST

The long technical explanation.
Most low-cost USB to Serial adapters (also called USB to RS232 adapters or converters) are not "true serial", they handle only approximately 60% of the 'common' RS232 uses/devices, which means that they will only work with slightly more than half of all commonly used serial devices such as printers, GPS units, handheld devices, scales, cameras and other typical serial devices.

Other problems you might experience with a low-cost adapter.
Due to latencies (data delays) and the way data is transmitted, a USB adapter cannot be 100% transparent to the device you are connecting to your computer, so among other things successful communication is a matter of timing between data sent from your computer, converted by the adapter and then received by your serial device. If this timing is off just slightly you will be unable to communicate successfully.
Many programs and devices were written and constructed for a serial port having a 16-character FIFO - or possibly for the original serial port that didn't have any FIFO at all. Several USB adapters have hundreds of bytes of FIFO, so it matters a lot if the data is sent using bulk transfers, and if the device is using any type of control transfer. This scenario is giving many low-cost adapters bad timing issues with many programs and devices, which in general means that it won't work properly with either your computer or the device you connect to the adapter.

USconverters.com does sell a low-cost adapter for customers who wish to use it with Windows 98, 2000 and XP, (here is an overview of all our USB to Serial RS232 adapters ) however for Windows 11 or 10 an Ultimate, Premium or Professional grade adapter such as one of these shown above is highly recommend.

What is limited compatibility?
Since most low-cost USB to Serial adapters are using a low-cost processor chip, these has only limited compatibility with Windows 11 and Windows 10. Limited compatibility means that either the adapter or the driver might or might not work with your Windows 11 computer, it all depends on your computer's particular hardware, installed Windows components and service packs, conflicting drivers and other pheriphial devices, and even your processors bios version.
A high-quality adapter with well-written drivers address all these factors which are hard-coded into the drivers and makes sure that all these processes, timing, hardware and everything else goes smooth so you can communicate with your serial device properly.