6 years later, still super slow. I hope Photoshop is replaced by Figma. 

Photoshop 23.2.0 It has been weeks of horrible performance. The moment I disabled Present Synching and closed the libraries tab everything was fast again.

Stay away fron synching if you photoshop starts slow with the neverending circling wheel.

Same problem here! No plugins installed. I guess it's a creative cloud problem that every time try to synchronize what you have in the cloud. If that's really the issue, please adobe allow your users to get rid of it or to disable creative cloud interaction with the entire cc suite.

Optimize Photoshop performance
https://helpx.adobe.com/photoshop/kb/optimize-photoshop-cc-performance.html#Broadstepstoboostperformance

I had the same problem, where Photoshop would take ages to start up or to open a file on a brand new top spec PC (Ryzen 5900X, RTX 3080, 32GB RAM, 1TB NVMe SSD). It was driving me crazy. But today I finally managed to fix it by going into NVIDIA Control Panel -> Display -> Set up G-SYNC and switching from "Enable for windowed and full screen mode" to just "Enable for windowed mode" (because I obviously still want to use G-SYNC for my full screen games). Now Photoshop works like a charm. I hope this helps someone.

I see that this is an old thread but it popped up when I googled "photoshop taking a long time to start up".  None of the above things worked for me.  I just installed photoshop on a brand new pc and it was taking about 3 minutes to start up.  I realized that I was never prompted to install Adobe AIR during this installation (which has been typical in my experience).  I went to the website, downloaded it, and now Photoshop starts up in less than five seconds.  Yay!

Just bumped in to this.

I'm new to Adobe CC and just paid for a year. Downloaded Photoshop and some other apps. The first thing I did was startup Photoshop and OMG, my first impression of this software is really horrible. I Cant belief I just paid 725 euro's for this.!

Using a newly fresh - last night - installed Windows 10 1803, Intel i7, 16GB ram, NVidia GTX 780 on 3 monitors with 3 SSD disks.

I do have a lot of other software installed: Numerous development tools and languages (Python, Haxe, VS 2017, Java, etc (most tools are registered in the %PATH%)). Also I have Cubase with a decent VST library... Perhaps part of the problem?

@ungoul Would you be so kind to share your solution? (Put it in a zip and share it though some cloud storage perhaps?)

I think I got it figured out and this is definitely a bug... I worked on a file on an external hard drive. The drive has been removed since I worked on the file, but that file is still being referenced in the "Recent Files" list when Photoshop starts. Photoshop is looking for the file or files and cannot find it, and this is causing the slow startup.

I changed the Recent Files to 0 under Preferences-->File Handling and that solved the issue. Photoshop starts up as normal again.

I downloaded driver boost and on the tools section I clicked clean unplugged data devices, this seems to have helped with the startup time.

I started experiencing similar issues a few weeks ago. Photoshop would appear to freeze immediately after showing the workspace. Clicking the menu bar would do nothing. Extension panels remain empty. Can't even move the window. Other applications on my computer continue to work normally. After being completely stuck for about a minute, Photoshop would return back to normal. This is on Windows 10 x64, 2017 fall creators update.

None of the solutions offered in this thread made any difference. Finally, I went to the Device Manager to check my graphics card status. Selecting View > Show hidden devices revealed the Intel HD graphics device next to the AMD R9 280 that I actually use. Nothing is connected to the Intel graphics and I thought I had disabled the device. After uninstalling the device and one more reboot, Photoshop startup times are back to normal.

Hope this helps, Campo