A few applications can be retrofitted to work correctly on Terminal Services via add-ons. The key class of applications for which this is true are applications which consume CPU cycles or memory.
For both issues, AppSense can be used for CPU clamping and memory limitation; it has quite a few other uses as well, including per-application and per-user control, with configurable setpoints for RAM/CPU use.
For CPU use by older 16-bit applications which perform intense keyboard polling, TameDOS is a good choice.
Issue: Cannot correlate user with IP address on a Terminal Server.
Will not work well with Terminal Services users, locally or remotely. The crucial issue is that they cannot differentiate between various TS users on the same IP. None of the open-source identd servers I have found as of 2002.09.02 will work.
Workarounds: None as of yet. Code for several Win32 implementations is open and could be retrofitted.
Issue: Must run in at least 16-bit color; CPU use at start.
It runs on console on Windows 2000; it should also run even in virtual sessions on .NET. Unfortunately it's a major CPU pig for a protracted period after launch due to script-fu.exe. This was tested with the 20001226 release of the Gimp. As of yet, the 1.2.4 rev Gimp is untested.
Workarounds: None known. Use other graphics applications which will work with 256 colors or upgrade to .NET. Alternatively, for light remote use a standalone XP Pro workstation could be used for graphics access.
Issue: Use is legally prohibited on a Terminal Server.
I have not been able to confirm this by viewing an actual EULA yet, but Sage reportedly explicitly prohibits use of Peachtree 2003 on a Terminal Server.
If this is indeed true, and if the lack of ability to use TS as a platform is an issue for you, it appears that you must decide between abandoning Terminal Services and abandoning new versions of Peachtree. Hopefully SAGE will provide an alternative in the near future.
Issue: CPU hog.
Typical tight keyboard polling loop consumes CPU cycles, causing significant performance degradation when even one session is running on a TS. Multiple or faster CPUs will not resolve this.
Workarounds: AppSense or TameDOS can control these applications. CPU addition if affinities are controlled by you could work, but is going to be less effective and more expensive.
Issue: Manufacturer says it will not work on Terminal Services. This can be indicative of a market retreat, so I would suggest considering other applications in the same niche when upgrading.