If you're mining a valid block, and you switch to another block that's not valid while mining, that other block seems to pick up the progress as well. If you rapidly alternate between two blocks, one valid and one not valid, you will eventually be able to mine them both.

This example was recorded from a clean copy of Minecraft with only Forge and MultiMine: https://www.youtube.com/watch?v=inoGPb9svxA

Note that in the example, I am using an unenchanted gold pickaxe to mine bedrock, simply by targeting the stone first.

I can't help you at all unless you specify which version of the mod you were running. There is a debug option in the config which you can enable (it will print tons of information in the console) - i would like this information.

I apologize. I'm using the 1.7.10 version of the mod. The log is here. I did some more bedrock mining to make sure the log included information about that. Note: the point in which I entered creative mode was simply to place blocks. The actual mining took place in survival mode.

Well, i did re-do almost all of this code in subsequent versions to fix this problem. I'll check if backporting the current version to 1710 is at all feasible.

Thank you. I'm using this mod in the Survival Industry modpack, which is stuck at 1.7.10 until Reika decides to go to a newer version of Minecraft. I like the way this mod works, and I really want to keep using it. However, it does pretty much nuke the mining progression I had set up.

In the meantime, I'll try and ban some blocks to mitigate the issue.

Please do a bit more testing when you can and i will make this the new default 1710 version.

Will do. I also have my modpack team working on it.

Here is a port of the 1.10.2 codebase to 1.7.10, a quick test shows it doesnt immediatly crash. Try it

https://drive.google.com/file/d/0B19yx7D_ef7vTlFTdjNfMWRUMG8/view?usp=sharing

A quick test shows that the exploit isn't happening with this one. For now, I think we can chalk this one up into the "win" column. I'll add it to Survival Industry, and see if any error reports crop up.

As far as we can tell, the problem is completely solved, and no side effects have been seen to this point. I think it's safe to say that it's safe to make this the default for 1.7.10.