Can't open bib files in Emacs. Please advise

I get this error when I try to open a `.bib` file in Emacs ​ ​ `Warning (undo): Buffer ‘reoigjrg.bib’ undo info was 29831394 bytes long.` `The undo info was discarded because it exceeded \`undo-outer-limit'.` ​ `This is normal if you executed a command that made a huge change` `to the buffer. In that case, to prevent similar problems in the` `future, set \`undo-outer-limit' to a value that is large enough to` `cover the maximum size of normal changes you expect a single` `command to make, but not so large that it might exceed the` `maximum memory allotted to Emacs.` ​ `If you did not execute any such command, the situation is` `probably due to a bug and you should report it.` ​ `You can disable the popping up of this buffer by adding the entry` `(undo discard-info) to the user option \`warning-suppress-types',` `which is defined in the \`warnings' library.` `Disable showing Disable logging` `Warning (undo): Buffer ‘reoigjrg.bib’ undo info was 27472005 bytes long.` `The undo info was discarded because it exceeded \`undo-outer-limit'.` ​ `This is normal if you executed a command that made a huge change` `to the buffer. In that case, to prevent similar problems in the` `future, set \`undo-outer-limit' to a value that is large enough to` `cover the maximum size of normal changes you expect a single` `command to make, but not so large that it might exceed the` `maximum memory allotted to Emacs.` ​ `If you did not execute any such command, the situation is` `probably due to a bug and you should report it.` ​ `You can disable the popping up of this buffer by adding the entry` `(undo discard-info) to the user option \`warning-suppress-types',` `which is defined in the \`warnings' library.` `Disable showing Disable logging`

Run "emacs -Q" and thrn open the .bib file. If it suddenly works, then one of your packages / hooks modifies the opened bib file.

Is that file supposed to be 29 MB big?

I think one of my packages/hooks as u/holgerschurig suggested did something to my bib files and they are suddenly too big for Emacs to handle. I removed a hook and a global mode then created a new bib file. That did it.