Perform a hard shutdown on the computer. Memory leakages from various applications will consume the physical RAM over time. This is especially true for computers left on for several days. A warm reboot will not guarantee that the physical RAM has been completely cleared. Your virus &/or Malware scanning software may be scanning every file as it is loaded. Try disabling your virus/malware software temporarily to see if it makes a difference. Your computer could be bogged down with Spyware, Malware, or viruses (Potentially Unwanted Programs (PUP)) - Try running cleaning / checking software such as MalwareBytes and spybot. (If you leave MalwareBytes installed, add C:\Program Files\Altium\AD[version#]\AltiumMS.exe to the Allow list) You might have too many other programs open on your computer. If your project files are on a server or in a folder that maintains an automated network or cloud copy such as OneDrive or Dropbox this can cause issues since it causes the files to be "in use", but Altium needs exclusive access. Also, the 'lock files' filename starts with ~$, which makes them incompatible with Microsoft's Onedrive for example. Try saving the project/files to a different location on your local hard drive to test. You can also try turning off auto sync, and sync manually if you really want to use a synchronizing folder. A better solution would be to use your Altium 365 Workspace to store your projects. A mirror of your project is created in the Workspace and synchronized. Saved local files are automatically synchronized with their mirrored project counterparts in the Workspace. The data from your Altium 365 Workspace is cached locally and is accessible in the event you are offline. When projects are opened from the Workspace, they are copied locally for offline access. Try launching Altium with "Run as administrator". In one case this cleared an issue causing a 90 second delay when trying to open projects for a customer that was using SVN. If you use scripts, check the number of custom Altium scripts loaded by going to Preferences > Scripting System > Global Projects page. Remove scripts that are not being used since they require system resources to be available "on demand." Your video board driver(s) may be out of date. A newer video card driver may resolve the issue. It's always a good idea to have the latest video board driver from the board manufacture's web page (rather than using Windows update or from Device Manager.) You can use the Windows control panel > Device Manager > Display adapters, to see what's installed, then go to the manufacturer's web page to download and install the latest driver. Video driver(s) note: If you've got a laptop, you might notice you have more than one display adapter. Update both drivers. There may be a way to set the GPU to be the card that gets used for X2.exe. For NVIDIA, You can manage the video settings in the NVIDIA control panel to set a default graphics card Open the Nvidia Control Panel. ... Select Manage 3D Settings under 3D Settings. Click on the Program Settings tab and select the program you want to choose a graphics card for (X2.exe) from the drop down list. You can also browse for X2.exe in this folder C:\Program Files\Altium\AD[your version] And try this: Click on Manage 3D Settings and open the drop down menu for Global Settings. Select the High-performance NVIDIA processor as your preferred graphics processor and click Apply." You can: Run DXdiag by clicking on the windows start button > type "Run" > press the enter key > type dxdiag > click OK > click the "Save All Information" button at the bottom > then send us the text file (attach it to a support case.) Also… Run MSInfo32 then use File > Save, give it a name.nfo …then attach the files to the case or send them to us. We can look through to find any information that sheds light on this issue. Check the System The Windows OS itself could be slowing down. This is most noticeable when running intensive applications. Check to make sure your version of Windows is up to date, that there are no pending updates to be installed or that have failed to install. Check for hardware faults, and run disk repair programs to ensure the file system integrity is 100%. Use the Windows System File Checker tool to repair missing or corrupted Windows system files. https://support.microsoft.com/en-us/help/929833/use-the-system-file-checker-tool-to-repair-missing-or-corrupted-system 1. Click on the windows start button 2. Type in CMD then from the results right-click on Command Prompt and select “Run as Administrator”. (afterward, you may need to click on yes to allow the app to make changes) 3. Type in “sfc /scannow” without quotes. 4. This process will verify their Windows Installation and replace any corrupted or missing DLL along with any other Windows protected system files. 5. Reboot the PC. Project Complexity and/or Issues Files imported from other systems may have many duplicated tracks or other problems that could be revealed by analyzing the design. In the PCB editor menu, Design » Netlist » Clean All Nets will remove stacked track segments. Note that it will not remove stacked segments if they are locked. For automatic optimization, go to Preferences > PCB Editor > General page. Enable the Smart Track Ends feature. Smart track ends will recalculate the nets so that they come from the track end rather than the shortest distance. Note: This feature is only useful on boards with low primitive counts and low density. On high density boards, it may actually slow the software down. Try working on one of the projects that comes with Altium Designer like Bluetooth_Sentinel.PrjPcb found in C:\Users\Public\Documents\Altium\[version]\Examples\Bluetooth Sentinel to see if you have the same slowness issue when that is the only project that is open. Then close all documents and open a simple example project such as the one in C:\Users\Public\Documents\Altium\AD20\Examples\SpiritLevel-SL1. Open the PCB and run Tools » Design Rule Check... Click the button "Run Design Rule Check...." This should only take a few seconds to run. If this simple check takes a long time, then there is something amiss with the installation of Altium Designer, or the system itself (see Check the System above.) If it runs quickly, then the problem is probably in the current design project, rather than Altium Designer itself. If you then think the Slowness is related to your project, you can use Project > Project Packager... to create a .zip file and send it to us so we can test it on our computers. If you think it is related to Altium Designer, try removing your preferences. Removing ("factory reset" of) your preferences which also clears Altium cache and some registry entries, may resolve this issue. See the choice for "Remove Preferences" while following the steps In this document (Save them first) Please note, this process will leave your Altium software in a freshly installed state, so if you connect to a private license or collaboration server, please record that information before starting this process.