Counter-intuitively, installing the Silent Patch often fixes this error because it updates how the game handles file I/O.
The most common culprit is Windows protecting your C:\Program Files folder from unauthorized changes. gta san andreas failed to open log file
This article will explain why this error happens and provide to get you back into San Andreas. gta san andreas failed to open log file
Here is a step-by-step guide to fixing this issue, ordered from the most likely solution to the least. gta san andreas failed to open log file
Alternatively, download the tool (for Steam users) which reverts the game to the more stable v1.0 executable.