There are other ways to fix this error, i’m sharing what works for me, hope it helps.
Delete all xml files except client.xml in “Steam\steamapps\common\TreeOfSavior\release” (user.xml, hotkey.xml, ETC) and restart the game. (if dont work first time, try again)
IPF error happens to me all time 
and i do it always.
Enjoy.
i just signed into another server then went back to mine and it never happened again.
If my way works for you, please tell me.
Didn’t work, but thanks for trying to help D:
A splash windows when selecting server that tell me:
I Know the a possible solution is what you say LucianoShaman,
But now I’m redownloading, because it was the solution that the client gives, a friend redownloading have fixed it, so if redownloading doesn’t work will try that, but the reality is that we have a problem, cause we can’t publish this like a problem solution, we need a real and professional solution for the game. Using old update system always will bring problem of this type.The mostly of us have this problem coming from line connection you need to get the game in 20 or 30 minutes with a High line connection of 50 ~ 100 MBPS for didn’t get a microbreak during download, but the mostly of us only have 1~10 MBPS that means that we need to wait 2 ~ 6 hours, so there are so many chances of get a microbreak in connection and to get one corrupt file while downloading, bring a olded update system (I know this update system so well, cause is so similar to Ragnarok 1 system) only will bring client crashes and file corrupting problems. Maybe a Check Files before installing with Checksum for MD5 hashes that will check all downloaded files, and another for check updated files after any update will be a very very good idea. Maybe this will take so much time the player for install or update the game, but you only need to do this the first time during installation and 1 time every week, or every month, and this can be an alternative or optionable because if you don’t need that, you can choose to skip the check files process. (in the installing process or in the update process) The same installer/updater can download the file or part that is lost or corrupt. (That will help players, on this way, players doesn’t need to redownload and reinstall the game [arround 2 ~ 6 hours waiting again & again] they only need to push check files button and only that file will be downloaded without any inconvenience, and players will stay, and not go out of the beta testing due the lack of time that they only need to download and install it). The point is begin the house from the floor, not from the roof. Maybe to improve the installer, updater and launcher must be a priority, after get a good launcher/installer/updater, you can center in basic in-game issues, and after that, to improve other bugs, like class balance, bosses, items, or NPCs don’t working right or others.
Hope this will help. Thanks you in advance.
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