topic Re: Horrifically unstable after 2026 updates in Fusion Support Forum

Horrifically unstable after 2026 updates

jason — Tue, 03 Mar 2026 22:00:25 GMT

Since the update(s) last month (design/assembly/hybrid), Fusion has been literally unusable for me.

Severe hanging (3-8 minutes to open/save files, edit in place), RAM maxing, crashing.

I have two Win11 PCs, in different physical locations (house/shop), with the exact same problems ; brand new Alienware i7/32RAM/5060 and 5 year old i9/32RAM/3090.

Old files (prior to 2026) are still slow but are at least usable and don't typically crash or hang.

Any new files (with or without assemblies) are unusable.

What has NOT worked; Latest update, Uninstalling and reinstalling, Converting new files to Hybrid, starting with files in hybrid, sent in crash reports every time.

Looking around the forums there appears to be major issues since moving to part/assembly/hybrid.

I would love to be able to use a product that I paid for, so what can I do to facilitate Fusion support?

Re: Horrifically unstable after 2026 updates

TheCADWhisperer — Tue, 03 Mar 2026 22:48:26 GMT

@jason wrote:
1. Old files (prior to 2026) are still slow but are at least usable and don't typically crash or hang.

2. Any new files (with or without assemblies) are unusable.

@jason

1. Can you attach an old file that is slow but at least usable as described in your problem statement.

2. For #1 can you pick something that you can attempt to reproduce from scratch for #2 to illustrate the difference?

Re: Horrifically unstable after 2026 updates

RajkumarIlanchelian — Wed, 04 Mar 2026 01:58:55 GMT

@jason Please also pass on any report IDs of crashes you have been sending in. This will help us to see all the reports from your machines.

Here is an article that could also be interesting to check out. There was a Microsoft update that caused very similar symptoms that you have called out.

https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/Fusion-freezes-on-Loading-additional-modules-and-won-t-startup.html

Re: Horrifically unstable after 2026 updates

jason — Wed, 04 Mar 2026 04:06:42 GMT

This wasnt as slow as other times but still took 1.5 minutes to close the part file (without saving). Performance report 108017
I'll try to isolate the problems.

Re: Horrifically unstable after 2026 updates

RajkumarIlanchelian — Wed, 04 Mar 2026 04:57:56 GMT

@jason thank you for sending in the performance report. We will have our engineering team take a look at it.

If you put Fusion in offline mode and run the same scenario, is it any quicker?

Re: Horrifically unstable after 2026 updates

jason — Wed, 04 Mar 2026 19:08:55 GMT

I opened the same file on my shop computer (as the last report when closing file); software is locked, RAM maxed out, CPU or GPU fan going full speed, file opened 2min later. That assembly file (which is 5 parts, nothing complicated), after opening, sits at 16-17Gb ram.

After opening, I stopped the recording to submit, but it also took 2min to close.

Report 108022.

I opened the same file in offline mode, still took 1min 50 sec to open, 3min 40sec to close.

Old file with more complexity; 3min 15sec to open, to close. This file with 4x more parts/joints is only 12Gb.

This report is literally just opening then closing the part file and is 9min long, lol.

Report 108023.

All of the above have been from a specific folder.

When trying older files (hybrid/assembly or single components) they're fine. So it appears it is this set of folder/files I'm using is inherently unstable/slow.

All of the above files are in a hub I'm an admin of, not my personal hub, so I made an archive of that assembly to move it into my personal hub. The export was quick but it took 4-5min to open my personal hub.

The file took 3 min to open the newly imported file from my personal hub but I noticed it imported 12 parts and the assembly file, but there is only 5 parts in the assembly. Those extra parts are shown in "used in" but all assembly contexts (in assembly file) are list as local.

I move all the unused parts to the trash and reopened the file, now showing "Nested unresolved components Expand to resolve components nested in this assembly". (Pic Attached)

There's something I've not seen before under the part/bodies/ folder; It still says Body1 but then has multiple other "context: context#(old file name) that are not visible (eye greyed out) and not selectable. Also appears to be referenced to itself.

I opened those 2 part files, deleted all the body contexts and saved.

When I reopened the assembly file, compute unresolved (3min), saved (2min). Then when I tried to close, it was hovering around 5-8% CPU, between 2.5-8Gb ram; after waiting 22 minutes it finally closed! That's not a typo, 22 minutes!

Upon reopening, it still took 5 min to open, then Fusion crashed on trying to close.

I tried to attach this file but it's 227Mb, which seems crazy for an assembly with a few parts.

I have now spent 10x longer troubleshooting Fusion than the job entire would have taken in Solidworks. 😢

Re: Horrifically unstable after 2026 updates

RajkumarIlanchelian — Wed, 04 Mar 2026 22:00:23 GMT

@Jason Thank you for the report IDs and the extra tests that you ran here. I am going to connect with our engineering teams to look at the reports.

@sanjana.shankar.goli Sanjana, can you please help with a first look?

Re: Horrifically unstable after 2026 updates

jason — Wed, 04 Mar 2026 22:05:51 GMT

After deleting all the weird context, those files still have issues.

So I rebuilt the files (using hybrid) from scratch and put them into a new assembly file and it seems ok now.

Re: Horrifically unstable after 2026 updates

sanjana.shankar.goli — Thu, 05 Mar 2026 05:57:07 GMT

@jason Thank you for sending the performance reports. I logged FUS-238644 , FUS-238646 tickets for both reports 108022, 108023. We will have some insights once our team investigates them.

Re: Horrifically unstable after 2026 updates

stringwringler — Thu, 05 Mar 2026 14:45:34 GMT

Something fishy is clearly going on here. I can confirm all what the OP describes and I am on Windows 10. This is clearly not a graphics performance issue but rather file related. The times to open, close, update or moving timeline in an assembly is off the charts. Minutes to open files, close files. Even when they are not touched. Moving the timeline in the assembly (16 parts) takes a coffee break to complete when at its worst. Fusion crashes about 50% of the times when some of the mentioned operations drags or fail to complete.

Older assemblies or parts are no problems. Quick open, quick close.

Re: Horrifically unstable after 2026 updates

RajkumarIlanchelian — Thu, 05 Mar 2026 15:39:54 GMT

@stringwringler Would you be open to inviting a couple of our engineering teams into your project where you are experiencing this issue? If so please let us know and we can send you details.

Re: Horrifically unstable after 2026 updates

Almeida1035HNZJ8 — Thu, 05 Mar 2026 17:20:46 GMT

Having similar issues. I had to scrap a design due to this. When I would try to edit a sketch I would get weird blurry blue lines for the sketch and the program would freeze.

Re: Horrifically unstable after 2026 updates

stringwringler — Thu, 05 Mar 2026 17:35:10 GMT

Yes, no problems. Please advice. /Thom

Re: Horrifically unstable after 2026 updates

RajkumarIlanchelian — Thu, 05 Mar 2026 21:20:26 GMT

@stringwringler I have sent you a DM

Re: Horrifically unstable after 2026 updates

sanjana.shankar.goli — Fri, 06 Mar 2026 04:15:34 GMT

@jason I've sent you a DM for some more information

Re: Horrifically unstable after 2026 updates

jason — Fri, 06 Mar 2026 20:27:47 GMT

Haven't seen anything come through.

Just wanted to say I used those newly created files all day yesterday and had zero issues.

Re: Horrifically unstable after 2026 updates

stefanTLDAL — Fri, 13 Mar 2026 19:13:55 GMT

I have been using fusion 360 now for 8 years (a few thousand hours). I have to say that the latest update has been a nightmare. Old drawings that became unusable (updating components stopped working, removing or breaking the link stopped working). A lot of freezing in between tasks or simple open and closing. drawings that were corrupt after a program shutdown because of hanging software. I am running fusion 360 on the following specs:

Windows 11 pro Processor (CPU) AMD Ryzen 9 8940HX 16 cores / 32 threads Turbo tot 5.3 GHz Grafische kaart (GPU) NVIDIA GeForce RTX 5060 Laptop GPU 8 GB GDDR7 VRAM Geheugen (RAM) 64 GB DDR5

This should be more than enough, but somehow fusion 360 now works worse on a laptop with all the best specs than a few years back on an old laptop.

I have been using this software professionally for my company, the uncertainty that every new update brings is really testing the enthusiasm I always felt for this program.

Re: Horrifically unstable after 2026 updates

stringwringler — Fri, 20 Mar 2026 16:33:46 GMT

Any news on the problematic assembly of mine? I scrapped my second attempt and started a third assembly with the same components after unlinking all the corrupt asm contexts. This made workflow significantly faster for a while. When the last component was assembled however, the excessive lag was back again.

Re: Horrifically unstable after 2026 updates

jfluecki — Wed, 01 Apr 2026 04:14:34 GMT

Any news.... I am definitely seeing the same thing. I have tried on 3 computers. It is unusable...

Re: Horrifically unstable after 2026 updates

lauri_barnhart — Thu, 02 Apr 2026 13:16:32 GMT

Hi @stringwringler and @jfluecki,

I wanted to check in and see if you still needed assistance, or if you found a solution to your question already? Let us know if you need further assistance by providing an update or if you have found a solution, please share it with the community so other members who may have the same question could learn from your experience.

All the best,

Lauri | Community Manager