Established in 1984, Mistral is proud to be widely considered the 'generic' software system provider for the refrigeration & air conditioning industry. In its domestic market, Mistral software is used by more than 85% of refrigeration & air conditioning contracting firms and programs have been distributed to over 17,000 users in over 100 countries around the world.


Error #902 seen when trying to install Mistral software means the code being attempted to be used is a genuine Mistral Registration Code and it is currently valid. However it is failing to install because you are trying to install programs which have since been upgraded. This means that you must send the code you are attempting to use by clicking here and Mistral will return a new updated access registration code for you. Generally within 24 hours and usually much sooner when during normal office hours (CET).


Error #904 seen when trying to install Mistral software means the code being attempted to be used is not a genuine Mistral Registration Code. Meaning it has been entered incorrectly.

Mistral's alpha-numeric access Registration codes have been made as easy as possible to enter. Firstly by eliminating letters in codes which can easily be confused. For example 'O' and '0' or 'I' and '1' or 'l'. Secondly by making codes non 'case sensitive'. In other words letters used in codes may be entered using either capitals or 'lower case' (small letters) with equal effect.

If having difficulty entering codes, and which can happen with exceptionally small computer monitors or for people with impaired vision, then try 'Copying & Pasting' the entire 24 character code, including the hyphens, directly into the code entry dialog box.


Error #905 seen when trying to install Mistral software means the code being attempted to be used is a genuine Mistral Registration Code. However if it is failing to install legally obtained Mistral programs then this will be due to one of three faults at the installer's end. Mistral's records show that reasons number 1) and 2) below are the most likely.

1) The Access Registration code is out of date.

Either because the code applies to a licence to use programs and interactive databases which are no longer current or because the code itself has passed its 'use by date', which is 90 days from the date that it was generated. Authorised licensees may apply to Mistral to issue them with a new code providing their licence is currently valid and this will be sent free of any charge. Access to programs and databases once installed will of course continue for the duration of the licenced period (either annual or 'lifetime'*) even when the code used to install them has passed its 'use by date'.

2) The Access Registration code is the wrong one for the program.

The Access Registration code that is being tried to be entered belongs to a different program issue. Either by date (a previous version for example) or to a completely different program or set of programs. (E.g. a code designed to install an individual program being applied to try and install Mistral's ‘Corporate’ program collection). Check to ensure you do not have more than one set of the Mistral program setup files (in a different folder) and that you are in fact trying to install the set intended. So as to avoid confusion unzipped program file sets from previous, now ‘time expired’ issues should be deleted from your computer.

3) The computer's system clock has been changed.

The target PC for installation has had its system clock reversed (either intentionally or accidentally set to an earlier date) at some time and then an attempt made to install Mistral’s intellectual property (software). This will introduce a blocking response in the affected computer and which can only be reset by an authorised Mistral engineer or manager (or a hard drive format). This is not just to protect Mistral against the consequences of intentional theft of its intellectual property (accessing software out of licenced time) but also to protect bona-fide licensees from accessing out of date code or no longer current data. The block will persist even if the system clock is subsequently reset correctly before an attempt is made to re-install (a ‘ratchet’ mechanism is employed which once set cannot be reversed without special measures). Mistral reserves the right to charge a fee for removing installation blocking codes. Particularly where there is evidence or a history of abuse.

* Programs installed using a 'Lifetime Licence' may not work correctly or may even cease to work altogether if the computer's Operating System is changed. This is because upgraded verions of Microsoft Windows frequently contain changes which affect program operation and which could not possibly have been anticipated by computer software developers at the time their programs were created. In this event it will be necessary to obtain the corresponding upgraded and compatible programs from Mistral. Program upgrades will NOT normally be offered free of charge! However, bona-fide lifetime licensees can expect to receive a substantial discount on the price of program upgrades. Mistral 'Corporate Licence' registered users all have their programs upgraded automatically as and when required, without incurring any additional charges.


Error #906 seen when trying to install Mistral software means the code being attempted to be used is for a different country or region of the world.

There are many diferent versions of Mistral programs which are designed to cope with regional variations. Such as those countries using commas as decimal point deliminators instead of full stops or countries normally using Imperial units of measurement instead of SI (System Internationale or metric).

Request a new Registration Code or in some cases also the re-issue of the software but set for the region you are in or if your computer is set for a different region to the one you are actually in (not uncommon!) then for the regional setting of that computer.

If in doubt run Mistral's SETUP.exe program again but before proceeding please press 'Ctrl' + 'V' keys simultaneously. A form should appear which displays (amongst other things) 'System Locale:' and 'User Locale:' . Please advise us the code letters against each of these and we will revert as appropriate with the solution.


Error #909 seen when trying to install Mistral software means the code being attempted to be used is a genuine Mistral Registration Code but it is no longer valid. This means that you must obtain a new access registration code and which you may do so by clicking here. If you, or your organisation if relevant, are holding a current licence then Mistral will return a new updated access registration code for you. Generally within 24 hours and usually much sooner when during normal office hours (CET).


Error #914 seen when trying to install Mistral software means the code being attempted to be used is a genuine 'single licence one time use only' code but which has already been used to install. Possibly by another authorised licensee.


Manual (not connected to Internet) Registration Procedure. During normal office hours (CET/CEST) only.

Mission statement:

"Bringing the benefits of computerisation to our industry - without the historically associated problems."