Reasons of IS/IT system failures.!

As I searched the net, I found out the causes of IT/IS systems failure are the following:

POOR DEVELOPMENT PRACTICES.
It means that the creator have faults in testing the program or he made some incorrect assumptions that were used in making the system or that there is poor data collection and documentation or that the system made has a poor user interface. The person who is developing the system is the one at fault in this type of failure for he is the one who is accountable for creating and maintaining the system.

INCORRECT ASSUMPTIONS WITH REGARDS TO SYSTEM REQUIREMENTS.
This type of failure holds the developer or the user accountable. Data is the most important factor in making systems for it is the basis for what the system does or what are its limits and requirements. Having incorrect data through making assumptions without clear outputs and using it in the system can lead to an ineffective system.

POOR USER INTERFACE .
Such failure can create a problem for the user of the system and therefore the chances of the user to input an incorrect data or receive an erroneous output.

FAULTY/AGING HARDWARE.
Its a problem that can create a grave system malfunction. This problem is caused by damaged or old or a badly designed hardware or by the user, who does not have enough resources needed to make the system effective.

END USER OR ENTITY PROBLEMS.
Basically if the user lacks training/knowledge in using a system, one can assume that he may have provided erroneous specifications and incorrect data thus creating an inefficient system.

POOR FIT BETWEEN SYSTEMS AND ORGANIZATION.
This problem comes about when neither the system developer or the user, grasp the idea of the system that they need to deal with.

POOR INVESTIGATION AND SYSTEM WITHOUT CHECKPOINTS.
Such problems can also result to failure because it means that the developer executed a wrong analysis in creating the system or didn't provide for back-ups or checkpoints for the system can result to an inefficient software.

Lastly, other external reasons such as Natural disaster (e.g., fires, floods, storms, or earthquakes) and electrical power variation while creating/ testing/ using the system can also result to the failure of the system processes.

Reference Sites:
http://www.benmeadowcroft.com/reports/systemfailure/

http://web.njit.edu/~turoff/coursenotes/IS679/679newset4/679set4/sld064.htm