The included NikonScan software for Windows & Apple Macs is a good starting point. It will probably be sufficient for most user's needs and I'd recommend it for new users. With the settings at "factory default", NikonScan will generally produce excellent scans and a base from which to experiment further. Various editions of NikonScan can work with all Windows versions and early MacOS versions with appropriate hardware; see below for details.
Both alternatives to NikonScan are "paid-for" packages which may offer more functionality but at the cost of complexity. VueScan supports a vast number of current and legacy document and photo scanners. They offer a full-featured free trial download (with watermarked scans) and a good value purchase price. Silverfast offers model-specific software aimed more towards the professional user with options such as IT8 calibration using their target media.
Article ID 000002288:
(Computer System Requirements for Nikon Scan software)
Version 4.0.3 was the final release of Nikon's Coolscan scanning application for Windows. It was intended for the 32-bit Windows Vista but also runs without modification in the 32-bit versions of Windows7 and Windows 8. Nikon did not produce Coolscan drivers to run under any 64-bit version of Windows but with some fairly simple manipulation of drivers, version 4.0.3 will run under all modern Windows versions. Note that on Windows XP, version 4.0.2 is needed which is functionally identical.
My notes detailing the 64-bit work-around procedure may be found here: NikonScan in 64-bit Windows - Detailed Instructions. The modified drivers may be downloaded from OneDrive here. The original driver work was done by "steel chn", a member of the Photo-net Digital Darkroom forum; if interested you can see the very lengthy thread here.
NikonScan version 4.0.2 was the final release of the MacOS software and the last supported MacOS version was 10.4.11 running on PowerPC Mac. Although the later Intel Macs were never supported by Nikon, Apple provided the Rosetta software to enable Intel machines to run PowerPC programs. This first version of Rosetta ran on OSX up to and including 10.6.8 Snow Leopard. To install NikonScan 4.0.2 on an appropriate Mac download the Nikon CD image file from my Downloads page and burn a physical CDR. The Mac installation software then runs automatically on disc insertion (the CD contains both Mac and Windows installation files).
Unlike the Windows situation, there is no known work-around to allow modern Macs to operate with the Mac versions of NikonScan. However it is possible to run a Windows OS on a Mac and then Windows NikonScan within this. One technique is to run a "virtual machine" and another uses Bootcamp. The following notes describing these techniques were kindly provided for publication here by Coolscan user Russ Meacham in Australia: Two techniques for running NikonScan on a modern Mac - Russ Meacham
Assessing users' problems remotely can be difficult. When the user is running Nikon Scan, not only are the error messages more explicit than other software but the single "Factory Defaults" button quickly establishes a known state. Having the capability to run third-party software as well gives the ability to cross-check between this and NikonScan which can be very useful. I'd therefore recommend that all Windows and Mac-users have a NikonScan installation available regardless of which app they use routinely.
Consider obtaining an old (and therefore cheap) computer on which you can install a contemporary operating system and the appropriate Nikon Scan software. As a stand-alone scanning host without a network connection there are no security issues with running a legacy OS. For Windows, look at a 32-bit PC with XP or 32-bit Windows7; for Mac look at a Mid-2010 Mac Mini running 10.6.8 Snow Leopard with Rosetta installed.
Further Information:
I am based in Lincoln UK If you have a Coolscan scanner in need of service or repair then please contact me by emailing coolscanuk@gmail.com Please allow a few days for a reply. Be aware that I do have a waiting list for scanner servicing.