I’m new to Blender, I created an set of models with textures, images etc. upon saving my work and closing it, I reopened it to find everything is black. I looked online and it said I had to save the textures through file > external data > pack resources, so I started a new project, got to a good point and then saved and closed, and I’ve gone back to see it’s all black again! even the objects without textures e.g. just a random cube I added to see if that would go black too? Does anyone know what is causing this and is there anything that I can do?
I think what opens on a black screen is saved in the material preview scene.
After saving in solid view, open the scene, hide all objects, create a simple object, apply it to the material using the image, and test it with material preview.
If this process is processed normally
The above problem is probably due to the GPU’s poor handling of the material of the big scene.
Try reinstalling the graphics driver.
Similar issues have been seen with graphics drivers that have been updated 2 times recently. (Personal Experience) 
What version of blender are you using? Since you are new to blender, I assume you downloaded the current 4.2 version. I ask this because I just experienced the same problem - everything was black.
In my case, I didn’t have any image textures. The materials were all very basic. The file was created in blender 3.6.5 LTS. The file opens fine in blender 4.0, but all objects appear black when opened in 4.2.1 LTS.
For me, it’s a problem with the new EEVEE renderer. My hardware won’t support the new renderer and all my objects appear black. Changing the render engine to Cycles fixes the problem.
Randy
I guess the EEVEE problem is correct.
And I think the cause is the graphic driver.
In Windows Safe Mode, the problem has been resolved by uninstalling the existing drivers and NVIDIA control panel from the mode and then reinstalling it.
I think there was a change in the graphics driver at a certain time. Estimated after September.
It’s a personal presumption. 