# MAGeCK count CRISPR screening

**URL:** <https://help.galaxyproject.org/t/mageck-count-crispr-screening/10126>\
**Category:** usegalaxy.org support\
**Tags:** metadata, datatype, genome-annotation\
**Created:** [May 25, 2023, 2:29am UTC](https://help.galaxyproject.org/t/mageck-count-crispr-screening/10126 "2023-05-25T02:29:07Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![jennaj](https://sea2.discourse-cdn.com/flex020/user_avatar/help.galaxyproject.org/jennaj/32/27_2.png) [@jennaj](https://help.galaxyproject.org/u/jennaj)\
**Post date:** [May 26, 2023, 1:39am UTC](https://help.galaxyproject.org/t/mageck-count-crispr-screening/10126/2 "2023-05-26T01:39:00Z")

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Welcome, @angel

Tools screen for specific datatypes when accepting inputs. For this input, the tool is expecting a dataset with the **tabular** datatype assigned.

 ![Screen Shot 2023-05-25 at 6.06.47 PM](https://us1.discourse-cdn.com/flex020/uploads/galaxy/original/2X/5/55781eac3bd3907de8e8a09d83cf00fc683f3e26.png)

**How to know which datatype a tool is expecting is in this topic and a few others.**

> [@fastq unavailable -- Tool does not recognize inputs? How to check why](https://help.galaxyproject.org/t/fastq-unavailable-tool-does-not-recognize-inputs-how-to-check-why/8925/2):
>
> if you are ever not sure what datatype(s) a tool accepts as input, any tool not just those that accept reads, try this:
> 
> 1. Create a new empty history
> 2. Load up the tool form
> 3. Review the input datatypes listed in the tool form’s input area
> 4. Note: A tool could have more than one input area and this works for all user-supplied inputs from the history.
> 
> **Example**
> 
> ![what-datatype-is-accepted-input](https://us1.discourse-cdn.com/flex020/uploads/galaxy/original/2X/e/e526ccad7216bc30f1408215478e172bbae0cda4.png)

Search: [Search results for 'tool doesn't recognize input' - Galaxy Community Help](https://help.galaxyproject.org/search?q=tool%20doesn%27t%20recognize%20input)

* * *

* * *

**Situations when the (unavailable) message can be generated**

1. Dataset 72 was originally accepted by a tool run.
2. It had a tabular datatype assigned, or was drag-and-dropped.
3. The latter breaks some built-in checks – you can try this way but expect problems exactly like this.
4. Or, the first was done, but the **datatype** assigned to dataset 72 was modified to be something other than tabular.  
 → When the “rerun” function is used to load up the tool form, it preloads what was originally input. If the metadata datatype was changed to be anything other than tabular, it won’t be accepted.

Keep in mind that none of this is about the file _content_. The data still needs to be in tabular format and have data in the columns it can understand.

Examples are down in the help section of the tool form. The GTN also has tutorials.  
[https://training.galaxyproject.org/training-material/search?query=MAGeCK](https://training.galaxyproject.org/training-material/search?query=MAGeCK)

There is a training event going on all week if interested. It is not too late to join. The bonus is a dedicated chat per tutorial, and the authors and other Galaxy scientists are there to help (including me). [Smörgåsbord 3: A week of Free, Online, Galaxy Training supported by the Global Galaxy Training Community](https://help.galaxyproject.org/t/smorgasbord-3-a-week-of-free-online-galaxy-training-supported-by-the-global-galaxy-training-community/9786)

Hope that helps! 🛠 🧑‍🔬 🙂

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_[View the full topic](https://help.galaxyproject.org/t/mageck-count-crispr-screening/10126)._