# Error: Unknown character ' ' in parenthesis notation?
**URL:** https://forum.eternagame.org/t/error-unknown-character-in-parenthesis-notation/5141
**Category:** Bug Reports
**Tags:** issue-resolved
**Created:** [November 7, 2024, 9:45pm UTC](https://forum.eternagame.org/t/error-unknown-character-in-parenthesis-notation/5141 "2024-11-07T21:45:37Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@terraofearth](https://forum.eternagame.org/u/terraofearth)
#### Post date: [November 7, 2024, 9:45pm UTC](https://forum.eternagame.org/t/error-unknown-character-in-parenthesis-notation/5141/1 "2024-11-07T21:45:37Z")
Hello! This problem might just be on my side, but some puzzles have read “_Error: Unknown character ’ ’ in parenthesis notation_” when I try to access them. This error appears with a couple of different “unknown characters” and typically happens when going through the challenges collection.
Some examples of these puzzles are:
[Eterna](https://eternagame.org/puzzles/383617/play)
[Eterna](https://eternagame.org/puzzles/15837/play)
[Eterna](https://eternagame.org/puzzles/15855/play)
[Eterna](https://eternagame.org/puzzles/26017/play)
[Eterna](https://eternagame.org/puzzles/15950/play)
Is anyone else running into these problems?
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### Author:  [@DigitalEmbrace](https://forum.eternagame.org/u/DigitalEmbrace)
#### Post date: [November 7, 2024, 11:36pm UTC](https://forum.eternagame.org/t/error-unknown-character-in-parenthesis-notation/5141/2 "2024-11-07T23:36:34Z")
Thank you for reporting the problem. I am getting the error also.
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### Author:  [@LFP6](https://forum.eternagame.org/u/LFP6)
#### Post date: [November 13, 2024, 4:46pm UTC](https://forum.eternagame.org/t/error-unknown-character-in-parenthesis-notation/5141/3 "2024-11-13T16:46:36Z")
Until recently we turned invalid structure characters into unpaired bases. I’ve updated these puzzles (as well as the other “difficulty levels” and a few other puzzles I could find that had the same issue) to explicitly use unpaired bases so that they’re back to working as they were - as well as adding “admin notes” in the descriptions when this means that the structures don’t match the structures that they were intended to be derived from (in most of these cases, an extra base was added from the originals coming from scientific literature).
Please let us know if you see any other puzzles with this issue!
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### Author:  [@Hearsall](https://forum.eternagame.org/u/Hearsall)
#### Post date: [December 10, 2024, 11:46am UTC](https://forum.eternagame.org/t/error-unknown-character-in-parenthesis-notation/5141/4 "2024-12-10T11:46:13Z")
I’ve just encountered a similar but different error message on trying to open [[NuPACK]Bulge hairpin pseudoknot](https://eternagame.org/puzzles/10472700): “Unbalanced parenthesis notation (found unclosed pair for character ‘{’)”. I don’t know whether this is related to the same issue or not.
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### Author:  [@LFP6](https://forum.eternagame.org/u/LFP6)
#### Post date: [December 11, 2024, 9:14pm UTC](https://forum.eternagame.org/t/error-unknown-character-in-parenthesis-notation/5141/5 "2024-12-11T21:14:15Z")
Yup, now fixed!
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### Author:  [@Hearsall](https://forum.eternagame.org/u/Hearsall)
#### Post date: [December 12, 2024, 10:24am UTC](https://forum.eternagame.org/t/error-unknown-character-in-parenthesis-notation/5141/6 "2024-12-12T10:24:00Z")
Thanks. Later I had the same problem with [[NuPACK]Second order pseudoknot](https://eternagame.org/puzzles/10472960). I’ve now tried all of Eli’s NuPACK pseudoknot puzzles and not found any others.
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### Author:  [@DigitalEmbrace](https://forum.eternagame.org/u/DigitalEmbrace)
#### Post date: [December 12, 2024, 12:27pm UTC](https://forum.eternagame.org/t/error-unknown-character-in-parenthesis-notation/5141/7 "2024-12-12T12:27:06Z")
Puzzle fixed!
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### Author:  [@Hearsall](https://forum.eternagame.org/u/Hearsall)
#### Post date: [September 3, 2026, 9:32am UTC](https://forum.eternagame.org/t/error-unknown-character-in-parenthesis-notation/5141/8 "2026-09-03T09:32:55Z")
This problem still exists in the [Puzzle of the Week version of [NuPACK]Second order pseudoknot](https://eternagame.org/puzzles/10961304).
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### Author:  [@DigitalEmbrace](https://forum.eternagame.org/u/DigitalEmbrace)
#### Post date: [September 3, 2026, 1:13pm UTC](https://forum.eternagame.org/t/error-unknown-character-in-parenthesis-notation/5141/9 "2026-09-03T13:13:22Z")
Parantheses are balanced now.