If both the Zip and the 7-Zip version fail to extract, go to 7-Zip and download the latest version.
The pack has been tested on all kinds of computers, from and old Pentium 4 running Windows XP to and modern i7 with Windows 10. There can only be a few things holding you back. Make sure you have your video card drivers, sound drivers and DirectX9 installed. When your are using windows 10 doing a Windows Update and running any modern pc game (like from steam) and it should be done.
Then go to the file properties of TacticalOps.exe and set it to "Run As Administrator". If this does not help disable "Data Execution Prevention" also known as "DEP", to do this search on google "How to disable DEP Windows".
When playing online multiplayer and the server changes maps, there is always a chance your game might crash. This is caused by addons such as NexGen, ACE or "bad/buggy" maps that are used by the server. The only fix for this is to (re)start the game and rejoin the server.
If your mouse cursor is stuck in the top left of the screen simply ALT-TAB out and back into the game. This happens when you click your right mouse button between the moment the Startup Logo has apeared and before the game goes fullscreen.
On some computers with Intel HD Graphics you might get a black screen when trying to start TO. This might depend on the model number and graphics driver used. It could help searching for a updated driver on Intel's website or your motherboard manufacturer. A work around is ALT+Enter 2x on startup to minimize TO, then make it full screen again and play the game. This has to be done every time on startup or set StartupFullscreen to False in "TacticalOps.ini"
File Mismatch errors should only happen when you install Custom Files manually into the game folder. When files are downloaded from a game server into the Cache folder this will not happen. So do not install custom files on a install that you also want to play online with. In the case you encounter a File Missmatch error when joining a server you can try to clean or delete the Cache folder, but most likely you will have to reinstall the game if you have not made a backup folder.
Install the ESESetup.exe for the ESE Account Manager. Make sure you have registered and obtained a ESE Keyfile and place it into your TO v3.5 System folder. Configure your TO v3.5 TacticalOps.exe installation folder in ESE. Then install the ESE Client Files and the ESE Renderers and configure them from inside the ESE Account Manager. After all these steps you should be able to join ESE Servers.
Also make sure to browse to the "System/TacticalOps.exe" file and not the Tactical Ops Quick Join.exe file when using the TO v3.4 + v3.5 fixed pack.
When using custom files its always advised to make a separate installation for offline use only.
.u, .ini and .int files -> TO-Version/System
.unr files -> TO-Version/Maps
.utx files -> TO-Version/Textures
.uax files -> TO-Version/Sounds
.umx files-> TO-Version/Music