JaariAtmc

Then 5 GB is still not enough. Try 8 GB.

Sigh. Only use Curseforge for your mods. You included mods from 9mc or similar that are already included in the modpack. Couldn't tell exactly which mod versions from 9mc, as that stupid site removes those.

Check your log. Does it still say "OutOfMemoryError"?

Get 64-bits java. 1 GB of RAM is not enough to run Tekkit Legends, you need 2-3 GB RAM allocated for that. You need 64-bit java for that.

Logs.

Get your mods only from Curseforge. Modpack.jar.jar Weather2 is for 1.7.10.

Probably a conflict between Optifine, Foamfix and Pixelcrap. Fix: Don't play pixelcrap. Fix 2: Don't make a second thread about the exact same issue.

java.lang.OutOfMemoryError: Java heap space 3.5 GB is not enough for 1.12.2 modpacks.

java.lang.OutOfMemoryError: Java heap space

Why are you still using Java 7 while most modpacks (like this one) require Java 8?

Nope, not even going to bother. Either you get your mods from Curseforge AND you actually look at the modpack guide or I won't even bother. Maybe 7 out of all your mods are NOT from curseforge. Probably 9minecraft. Don't.

Its literally the .exe you download. Just put it on your desktop.

Launcher Options > Open Logs. Take the relevant log (if you didn't try anything today, but did so yesterday, put in yesterdays log. I shouldn't have to tell you, but today's log is useless in this case/example).

How many chunkloaders are you using, and would removing them cause massive issues short-term?

Or you learn how to portforward.

Oh lovely, the IC2 bug I encountered in 1.6.4, for which no fix was available at the time, nor will it likely be available in 1.7.10. This is the issue for 1.10 (same issue), no fix really available either. https://bt.industrial-craft.net/view.php?id=1959

Delete TechnicLauncher.exe and delete .technic in Appdata -> Roaming. And, that's it.

Oh, you mean VanillaFix, the mod for 1.12.2, while BigDig is a 1.5.2 modpack. And this thread is 5+ years old.

Link no longer works.

Ever used MCleaks? Not that anything of value was lost, because pixelmon sucks.

You did check your spam folders, right? Cause that's where most of the technic mails seem to end up for me

Remove Java 8u221. After that, install Java 8 from this link: http://javadl.sun.com/webapps/download/AutoDL?BundleId=98428 Start up the launcher and try again.

Remove Java 8u221. After that, install Java 8 from this link: http://javadl.sun.com/webapps/download/AutoDL?BundleId=98428 Start up the launcher and try again.

Do not allocate 15 GB RAM when you don't have it available. In general, just don't allocate 15 GB. 8 GB is enough for modpacks. Sigh, always the same with people. "Oh, can only do 1 GB. It doesn't work. Lets use 64-bits java. Now suuuuuurely my max RAM minus 1 GB is totally going to work!!!!" ^This doesn't work, and people just have the issue from the other side (pc uses more than 1 GB normally. 2 GB - 1.x GB = <1 GB. 16 GB - 1.x GB = < 15 GB.).

no logs no help