If you've stumbled upon a blend1 file and are puzzled about what it is, or if you're trying to figure out what's eating up your hard drive space, you're in the right place.

In a nutshell, blend1 files are essentially previous versions of your current file, automatically stored in your working directory. But there's more to it than that – let's delve deeper.

Do you need blend1 files?

Chances are, you might not even need blend1 files. Let me paint a picture to illustrate why.

Imagine your early days with Blender: you’re experimenting, getting the hang of it. Initially, you don’t produce much worth keeping, but then inspiration strikes. You embark on an ambitious project, so engrossed that you forget to save your work for hours. And then, disaster strikes – your work vanishes!

You might blame Blender at first, but then you realize it wasn’t Blender’s fault at all. In your frustration, you discover Blender's lifesaving feature – the blend1 files that automatically back up your work. Relief!

So, you start creating backups obsessively. You’re saving every few seconds, and before you know it, every backup file is virtually identical.

Fast forward, and your approach to saving work evolves (more on that later), but your blend1 file habit sticks around. Result? A growing collection of hard drives crammed with these backups.

Sound familiar? If so, you're not alone.

So what is a blend1 file, and how do they work?

Let’s say you’re working on a file called “Cool_project.blend”

Usually, every time you save, this file is directly overwritten.  However, if you have blend1 files enabled before it is overwritten, the old filename extension is renamed to blend1.  And if blend1 already existed, it becomes blend2, and blend2 becomes blend3, etc..all the way up to however many copies you told Blender to keep (the limit is 32 saved versions).

How do you open or restore one of these backups?

Easy. Simply rename the file extension.

Change “Cool_project.blend1” to  “Cool_project.blend” and the old version of your file ready to open.

A Better Way To Work with Blend Files

Rather than naming your files in a random way and constantly saving over a single file until the project is finished, you should use a naming convention and start incrementing the name when it’s appropriate.

How to choose your naming convention

Having a naming convention will save you a lot of headaches in the long run.  There is no ‘correct’ naming convention but I will make 3 strong suggestions.

1. Be short.
2. Be consistent.
3. Use a logically placed numeral in the title.

You can evolve your naming convention as your skills and experience grow, but just make sure you are consistent across the same project.  This will make it easier for you to know what’s going on if you ever need to come back to the project months or even years later.  It also makes it easier for someone else to know what’s going on if they ever need to look at the project files.

Here are some examples of bad file names.

Project Cool_like_I_mean _really-really_cool-BEST ONE.blend
Cooler project2_bestest_than-the-last_one_final.blend
Even cooler version of the_first version_final_version3.blend

What!? Here’s an example of a better naming convention.

Cool_project_01.blend
Cool_project_02.blend
Cool_project_03.blend

Ahhhh, that’s much better.

It’s clean, consistent and so much easier to see which one is the latest version.

Why should you use a logically placed number in your file?

As mentioned, it makes it easier to tell which is the latest version plus Blender has a cool feature that easily lets you increment the number in the file name.

Just press the + button on screen (or the + button on the Keyboard) when saving and it will auto-increment the file number.

When do you increment your file name?

Usually, after you’ve done a fair chunk of work or you are about to do something that might be considered dangerous. That could mean many things, but you should be smart about it.  You need to start taking control of when these save points happen and don’t leave it up to chance.  When you take control of your saved versions like this, there is no need for blend1 files at all.  They are just taking up space on your hard drive.

You might be thinking that by turning off blend1 files you’ll be working without a safety net.

Not true.  You have everything incrementally saved so there is no situation where a blend1 file is going to save you more work.

What if you accidentally close Blender without saving?

Sometimes that can happen or a random crash can occur, but there are two features that can help you there.

 ‘Recover Autosave’ and ‘Recover last session’

Back in the old days, let’s say that these features were more ornamental than functional.  On the rare occasion, they worked, but more often than not they just restored a half-populated file of junk. However, in recent years, I am happy to say that they truly do work every time.

What is the role of Autosave in blend files?

Autosave files differ to the blend1 in 1 keyway.  They are temporary.  By default, Blender will automatically create a backup every 2 minutes and store these to your temporary folder.

These files can be opened when you choose ‘Recover Autosave’.  You can also see the timestamp and the process ID to know what version you want to recover.

These temporary files are cleared out every time you reboot your computer.

How to restore your last Blender session

When you quit Blender, a quit.blend is saved to that same temporary folder.  This file is opened when you choose to restore the last session. Perfect for when you accidentally closed without saving that last update.

Where can you tell Blender to put your temporary files?

As I mentioned above, the default temporary location on your OS is cleared out every time you reboot your computer.  This means it automatically cleans up after you, which is a good thing, but it also means that if you do encounter trouble, don’t think ‘Oh I’ll just go to bed and fix it in the morning’. You should recover the file before you reboot.

So do you really need blend1 files anymore?

I'm not suggesting that everyone should immediately stop using blend1 files. In the beginning, they can be real lifesavers, especially when you're still finding your way around. But as you gain experience and adopt good file management habits, the need for blend1 files, not to mention blend2s and beyond, becomes unnecessary.

When you're manually managing file versions and still saving blend1 files, you're essentially cluttering your hard drive—or your company's—with redundant data.

Wondering if it's time to break free from the blend1 routine? Consider a question that someone once asked me, which really put things into perspective for me.

When was the last time you needed to use a blend1 file?

If you’re struggling to answer that...it means that you are ready to ditch them forever.

Read: https://cgcookie.com/posts/how-to-organize-your-blender-files