Just got this from MS support this morning
Confirmed issue details
Environment Affected: Windows Server 2019 RDS, Citrix, Horizon desktop environments
Excel Version: Microsoft 365 MSO (Version 2507 Build 16.0.19029.20136), both 32-bit and 64-bit
Symptoms:
Black bar intermittently appears at the bottom of Excel, hiding sheet tabs
Menu/ribbon options may disappear
Theme colors not displaying in dropdowns
Issue typically occurs within 1–2 hours of Excel usage
Likely Root Cause
The issue appears to be related to UI rendering problems caused by Citrix VDA 2402 or similar virtualization layers. These platforms may mishandle Excel's graphics rendering, especially when:
Switching between applications
Using multiple monitors
Running Excel in full-screen mode
Why It Happens:
Citrix and Horizon use virtual display drivers and GPU passthrough (e.g., NVIDIA vGPU)
Driver mismatches between host and guest VMs can cause UI glitches
Hardware acceleration in Office apps may conflict with virtual drivers
Excel’s rendering engine expects consistent GPU behavior, which virtualization layers may not guarantee
Horizon 8 users with NVIDIA GPUs have also reported similar issues in Excel and Outlook
Workarounds & Fixes :
Rename Excel Cache File
Path:
C:\Users<username>\AppData\Local\Microsoft\Excel\CatalogCacheMetaData.xml
Rename to CatalogCacheMetaData_old.xml and restart Excel
Effect: Temporarily resolves the black bar issue
Disable Hardware Graphics Acceleration
Go to File > Options > Advanced > Display
Check "Disable hardware graphics acceleration"
Restart Excel
Avoid Full-Screen Mode
Use Excel in windowed mode, especially with multiple monitors
Resize or minimize/maximize the window to force a redraw
Use Keyboard Shortcuts
Use Ctrl + Page Up / Page Down to switch sheets when tabs are hidden
Switch Update Channel
Users have reported that the Semi-Annual Channel is unaffected
Consider switching from Monthly Enterprise Channel to Semi-Annual
Reset Graphics Driver
Press Win + Ctrl + Shift + B to reset the graphics driver
Helps in some cases with rendering glitches
Check Display Scaling
Set display scaling to 100%
Avoid custom scaling settings that may interfere with rendering
Below are the recommendations
Update Citrix VDA or Horizon Agent to the latest stable version
Match GPU driver versions between host and guest VMs
Disable hardware graphics acceleration in Excel
Avoid full-screen mode; use windowed mode and resize to force redraw
Switch to the Semi-Annual Channel for Excel if possible