Bugs are coding mistakes that cause errors during gameplay.
Known bugs for Colonization include:
Hopping Passengers
In Civilizations I & II, units sentried on ships could be activated at sea to transfer them between ships sharing the same space. In Colonization, units transfer between any in the same space whether they are activated or not. This can be especially frustrating when loading ships in Europe, as ships arriving from different points on the map can end up bringing the wrong passengers to the wrong locations in the New World. One kludge is to cheaply fill the holds of the other ships with 1 ton each of different cargoes, stopping the ships from being able to steal units during transit. This cargo can then be carried to a colony or dumped overboard.
Pathfinding
Units in Sid Meier's Colonization will optimize their paths on short routes. On longer ones, land units will take more linear routes even when it means ignoring roads or obstacles like lakes and inlets. Indian units can end up immobile when their direct path back to their original settlement becomes blocked by European units or colonies. On longer routes, inexplicably mimic great circle routes despite this frequently lengthing their journey. They also don't avoid offensive enemy units even though these frequently slow their passage, leaving them open for attack. Land units, on the other hand, will sometimes go needlessly out of their way (even in the opposite of the intended direction) when told to travel past an enemy unit, despite it being unable to block their passage.
Corner Squares
Normally, armed ships (privateers, frigates, men o'war) slow enemy ships passing by adjacent squares. However, when moving diagonally into the map squares diagonally adjacent to such ships, this effect is frequently avoided.
Random Number Generator
The original DOS edition of Colonization had a buggy random number generator that can lead to long strings of consecutive victories or defeats.
In the basic game, the only solution is to reload saved games or take other actions (such as movement or trading) that help to reset the counter.
In 2004, the user brut posted a fix at Civfanatics:
Do following. 1. Open viceroy.exe in your hex-editor. 2. Find such bytes: A3 EE 28 C7 06 3. Replace A3 with 5D, and EE with CB, so you get 5D CB 28 C7 06 4. Bug was removed!
This fix, however, produces the new bug that the game will consistently generate the same map on startup. To counter this, the original viceroy.exe file can be kept alongside a second vicefix.exe one that includes brut's edit. Begin the game normally, producing various new maps. Once a map has been created, load and play the map by starting directly from the vicefix.exe file.
A second fix tested to work in version 3.0 (Steam ed.) is to find the same bytes as before but replace C7 with 5D and 06 with CB. This produces much more randomized battles while still preserving the random map generator.
Cathedral Issues
In the early versions of the DOS edition of Colonization, cathedrals could only be built in colonies of size 16, rather than the correct size 8. This was fixed by one of the patches.
Unit destructed instead of demoted
Dragoons and Continental cavalry units in Sid Meier's Colonization that attack and lose the fight can randomly be destroyed intead of demoted.
Attacks during peace or without contact
Other European powers in Sid Meier's Colonization that you have met can randomly attack your colonies without declaring war and while keeping the peace status in the foreign affairs advisor screen.
Other European powers that you have not met can randomly attack you in the sea with frigates.